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Kramárek M, Souček P, Réblová K, Grodecká L, Freiberger T. Splicing analysis of STAT3 tandem donor suggests non-canonical binding registers for U1 and U6 snRNAs. Nucleic Acids Res 2024; 52:5959-5974. [PMID: 38426935 PMCID: PMC11162779 DOI: 10.1093/nar/gkae147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 02/02/2024] [Accepted: 02/16/2024] [Indexed: 03/02/2024] Open
Abstract
Tandem donor splice sites (5'ss) are unique regions with at least two GU dinucleotides serving as splicing cleavage sites. The Δ3 tandem 5'ss are a specific subclass of 5'ss separated by 3 nucleotides which can affect protein function by inserting/deleting a single amino acid. One 5'ss is typically preferred, yet factors governing particular 5'ss choice are not fully understood. A highly conserved exon 21 of the STAT3 gene was chosen as a model to study Δ3 tandem 5'ss splicing mechanisms. Based on multiple lines of experimental evidence, endogenous U1 snRNA most likely binds only to the upstream 5'ss. However, the downstream 5'ss is used preferentially, and the splice site choice is not dependent on the exact U1 snRNA binding position. Downstream 5'ss usage was sensitive to exact nucleotide composition and dependent on the presence of downstream regulatory region. The downstream 5'ss usage could be best explained by two novel interactions with endogenous U6 snRNA. U6 snRNA enables the downstream 5'ss usage in STAT3 exon 21 by two mechanisms: (i) binding in a novel non-canonical register and (ii) establishing extended Watson-Crick base pairing with the downstream regulatory region. This study suggests that U6:5'ss interaction is more flexible than previously thought.
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Affiliation(s)
- Michal Kramárek
- Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic
- Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, 62500 Brno, Czech Republic
| | - Přemysl Souček
- Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic
- Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
| | - Kamila Réblová
- Centre of Molecular Biology and Genetics, University Hospital and Masaryk University, Brno, Czech Republic
| | - Lucie Kajan Grodecká
- Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic
| | - Tomáš Freiberger
- Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic
- Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
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2
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Shen A, Hencel K, Parker MT, Scott R, Skukan R, Adesina AS, Metheringham CL, Miska EA, Nam Y, Haerty W, Simpson GG, Akay A. U6 snRNA m6A modification is required for accurate and efficient splicing of C. elegans and human pre-mRNAs. Nucleic Acids Res 2024:gkae447. [PMID: 38808663 DOI: 10.1093/nar/gkae447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 05/08/2024] [Accepted: 05/13/2024] [Indexed: 05/30/2024] Open
Abstract
pre-mRNA splicing is a critical feature of eukaryotic gene expression. Both cis- and trans-splicing rely on accurately recognising splice site sequences by spliceosomal U snRNAs and associated proteins. Spliceosomal snRNAs carry multiple RNA modifications with the potential to affect different stages of pre-mRNA splicing. Here, we show that the conserved U6 snRNA m6A methyltransferase METT-10 is required for accurate and efficient cis- and trans-splicing of C. elegans pre-mRNAs. The absence of METT-10 in C. elegans and METTL16 in humans primarily leads to alternative splicing at 5' splice sites with an adenosine at +4 position. In addition, METT-10 is required for splicing of weak 3' cis- and trans-splice sites. We identified a significant overlap between METT-10 and the conserved splicing factor SNRNP27K in regulating 5' splice sites with +4A. Finally, we show that editing endogenous 5' splice site +4A positions to +4U restores splicing to wild-type positions in a mett-10 mutant background, supporting a direct role for U6 snRNA m6A modification in 5' splice site recognition. We conclude that the U6 snRNA m6A modification is important for accurate and efficient pre-mRNA splicing.
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Affiliation(s)
- Aykut Shen
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
| | - Katarzyna Hencel
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
| | - Matthew T Parker
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Robyn Scott
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Roberta Skukan
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
| | | | | | - Eric A Miska
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Rd, Cambridge CB2 1QN, UK
| | - Yunsun Nam
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Wilfried Haerty
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
- Earlham Institute, Norwich Research Park, Norwich, UK
| | - Gordon G Simpson
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
- Cell & Molecular Sciences, James Hutton Institute, Invergowrie, DD2 5DA, UK
| | - Alper Akay
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
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3
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Rawat C, Heemers HV. Alternative splicing in prostate cancer progression and therapeutic resistance. Oncogene 2024; 43:1655-1668. [PMID: 38658776 PMCID: PMC11136669 DOI: 10.1038/s41388-024-03036-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/26/2024]
Abstract
Prostate cancer (CaP) remains the second leading cause of cancer deaths in western men. CaP mortality results from diverse molecular mechanisms that mediate resistance to the standard of care treatments for metastatic disease. Recently, alternative splicing has been recognized as a hallmark of CaP aggressiveness. Alternative splicing events cause treatment resistance and aggressive CaP behavior and are determinants of the emergence of the two major types of late-stage treatment-resistant CaP, namely castration-resistant CaP (CRPC) and neuroendocrine CaP (NEPC). Here, we review recent multi-omics data that are uncovering the complicated landscape of alternative splicing events during CaP progression and the impact that different gene transcript isoforms can have on CaP cell biology and behavior. We discuss renewed insights in the molecular machinery by which alternative splicing occurs and contributes to the failure of systemic CaP therapies. The potential for alternative splicing events to serve as diagnostic markers and/or therapeutic targets is explored. We conclude by considering current challenges and promises associated with splicing-modulating therapies, and their potential for clinical translation into CaP patient care.
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Affiliation(s)
- Chitra Rawat
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Hannelore V Heemers
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.
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4
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Zong Y, Zhang F, Wu H, Xia H, Wu J, Tu Z, Yang L, Li H. Comprehensive deciphering the alternative splicing patterns involved in leaf morphogenesis of Liriodendron chinense. BMC PLANT BIOLOGY 2024; 24:250. [PMID: 38580919 PMCID: PMC10998384 DOI: 10.1186/s12870-024-04915-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/15/2024] [Indexed: 04/07/2024]
Abstract
Alternative splicing (AS), a pivotal post-transcriptional regulatory mechanism, profoundly amplifies diversity and complexity of transcriptome and proteome. Liriodendron chinense (Hemsl.) Sarg., an excellent ornamental tree species renowned for its distinctive leaf shape, which resembles the mandarin jacket. Despite the documented potential genes related to leaf development of L. chinense, the underlying post-transcriptional regulatory mechanisms remain veiled. Here, we conducted a comprehensive analysis of the transcriptome to clarify the genome-wide landscape of the AS pattern and the spectrum of spliced isoforms during leaf developmental stages in L. chinense. Our investigation unveiled 50,259 AS events, involving 10,685 genes (32.9%), with intron retention as the most prevalent events. Notably, the initial stage of leaf development witnessed the detection of 804 differentially AS events affiliated with 548 genes. Although both differentially alternative splicing genes (DASGs) and differentially expressed genes (DEGs) were enriched into morphogenetic related pathways during the transition from fishhook (P2) to lobed (P7) leaves, there was only a modest degree of overlap between DASGs and DEGs. Furthermore, we conducted a comprehensively AS analysis on homologous genes involved in leaf morphogenesis, and most of which are subject to post-transcriptional regulation of AS. Among them, the AINTEGUMENTA-LIKE transcript factor LcAIL5 was characterization in detailed, which experiences skipping exon (SE), and two transcripts displayed disparate expression patterns across multiple stages. Overall, these findings yield a comprehensive understanding of leaf development regulation via AS, offering a novel perspective for further deciphering the mechanism of plant leaf morphogenesis.
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Affiliation(s)
- Yaxian Zong
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Fengchao Zhang
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Hainan Wu
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Hui Xia
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Junpeng Wu
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Zhonghua Tu
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Lichun Yang
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Huogen Li
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
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Gao W, Nie J, Yao J, Wang J, Wang S, Zhang X, Liu Y, Liu Y. Genomic survey and expression analysis of cellulose synthase superfamily and COBRA-like gene family in Zanthoxylum bungeanum stipule thorns. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2024; 30:369-382. [PMID: 38633272 PMCID: PMC11018584 DOI: 10.1007/s12298-024-01432-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 12/24/2023] [Accepted: 03/01/2024] [Indexed: 04/19/2024]
Abstract
The Cellulose Synthase gene (CS) superfamily and COBRA-like (COBL) gene family are essential for synthesizing cellulose and hemicellulose, which play a crucial role in cell wall biosynthesis and the hardening of plant tissues. Our study identified 126 ZbCS and 31 ZbCOBL genes from the Zanthoxylum bungeanum (Zb) genome. Phylogenetic analysis and conservative domain analysis unfolded that ZbCS and ZbCOBL genes were divided into seven and two subfamilies, respectively. Gene duplication data suggested that more than 75% of these genes had tandem and fragment duplications. Codon usage patterns analysis indicated that the ZbCS and ZbCOBL genes prefer ending with A/T base, with weak codon preference. Furthermore, seven key ZbCS and five key ZbCOBL genes were identified based on the content of cellulose and hemicellulose and the expression characteristics of ZbCS and ZbCOBL genes in various stages of stipule thorns. Altogether, these results improve the understanding of CS and COBL genes and provide valuable reference data for cultivating Zb with soft thorns. Supplementary Information The online version contains supplementary material available at 10.1007/s12298-024-01432-x.
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Affiliation(s)
- Weilong Gao
- College of Forestry, Northwest A&F University, Yangling, 712100 China
| | - Jiangbo Nie
- College of Forestry, Northwest A&F University, Yangling, 712100 China
| | - Jia Yao
- College of Forestry, Northwest A&F University, Yangling, 712100 China
| | - Jianxin Wang
- College of Forestry, Northwest A&F University, Yangling, 712100 China
| | - Shengshu Wang
- College of Forestry, Northwest A&F University, Yangling, 712100 China
| | - Xueli Zhang
- College of Forestry, Northwest A&F University, Yangling, 712100 China
| | - Yonghong Liu
- College of Forestry, Northwest A&F University, Yangling, 712100 China
| | - Yulin Liu
- College of Forestry, Northwest A&F University, Yangling, 712100 China
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Shamnas v M, Singh A, Kumar A, Mishra GP, Sinha SK. Exitrons: offering new roles to retained introns-the novel regulators of protein diversity and utility. AOB PLANTS 2024; 16:plae014. [PMID: 38566894 PMCID: PMC10985678 DOI: 10.1093/aobpla/plae014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/15/2024] [Indexed: 04/04/2024]
Abstract
Exitrons are exonic introns. This subclass of intron retention alternative splicing does not contain a Pre-Terminating stop Codon. Therefore, when retained, they are always a part of a protein. Intron retention is a frequent phenomenon predominantly found in plants, which results in either the degradation of the transcripts or can serve as a stable intermediate to be processed upon induction by specific signals or the cell status. Interestingly, exitrons have coding ability and may confer additional attributes to the proteins that retain them. Therefore, exitron-containing and exitron-spliced isoforms will be a driving force for creating protein diversity in the proteome of an organism. This review establishes a basic understanding of exitron, discussing its genesis, key features, identification methods and functions. We also try to depict its other potential roles. The present review also aims to provide a fundamental background to those who found such exitronic sequences in their gene(s) and to speculate the future course of studies.
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Affiliation(s)
- Muhammed Shamnas v
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
| | - Akanksha Singh
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
- Department of Botany and Plant Pathology, Lilly Hall of Life Sciences, Purdue University, West Lafayette 47906, Indiana, USA
| | - Anuj Kumar
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
| | - Gyan Prakash Mishra
- Division of Genetics, ICAR-Indian Agricultural Research Institute, Pusa Campus, New Delhi 110012, India
| | - Subodh Kumar Sinha
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
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7
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Larue GE, Roy SW. Where the minor things are: a pan-eukaryotic survey suggests neutral processes may explain much of minor intron evolution. Nucleic Acids Res 2023; 51:10884-10908. [PMID: 37819006 PMCID: PMC10639083 DOI: 10.1093/nar/gkad797] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 09/12/2023] [Accepted: 09/19/2023] [Indexed: 10/13/2023] Open
Abstract
Spliceosomal introns are gene segments removed from RNA transcripts by ribonucleoprotein machineries called spliceosomes. In some eukaryotes a second 'minor' spliceosome is responsible for processing a tiny minority of introns. Despite its seemingly modest role, minor splicing has persisted for roughly 1.5 billion years of eukaryotic evolution. Identifying minor introns in over 3000 eukaryotic genomes, we report diverse evolutionary histories including surprisingly high numbers in some fungi and green algae, repeated loss, as well as general biases in their positional and genic distributions. We estimate that ancestral minor intron densities were comparable to those of vertebrates, suggesting a trend of long-term stasis. Finally, three findings suggest a major role for neutral processes in minor intron evolution. First, highly similar patterns of minor and major intron evolution contrast with both functionalist and deleterious model predictions. Second, observed functional biases among minor intron-containing genes are largely explained by these genes' greater ages. Third, no association of intron splicing with cell proliferation in a minor intron-rich fungus suggests that regulatory roles are lineage-specific and thus cannot offer a general explanation for minor splicing's persistence. These data constitute the most comprehensive view of minor introns and their evolutionary history to date, and provide a foundation for future studies of these remarkable genetic elements.
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Affiliation(s)
- Graham E Larue
- Quantitative and Systems Biology Graduate Program, University of California Merced, Merced, CA 95343, USA
| | - Scott W Roy
- Department of Molecular and Cell Biology, University of California Merced, Merced, CA 95343, USA
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
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8
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Steinmetz EL, Noh S, Klöppel C, Fuhr MF, Bach N, Raffael ME, Hildebrandt K, Wittling F, Jann D, Walldorf U. Generation of Mutants from the 57B Region of Drosophila melanogaster. Genes (Basel) 2023; 14:2047. [PMID: 38002990 PMCID: PMC10671637 DOI: 10.3390/genes14112047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
The 57B region of Drosophila melanogaster includes a cluster of the three homeobox genes orthopedia (otp), Drosophila Retinal homeobox (DRx), and homeobrain (hbn). In an attempt to isolate mutants for these genes, we performed an EMS mutagenesis and isolated lethal mutants from the 57B region, among them mutants for otp, DRx, and hbn. With the help of two newly generated deletions from the 57B region, we mapped additional mutants to specific chromosomal intervals and identified several of these mutants from the 57B region molecularly. In addition, we generated mutants for CG15651 and RIC-3 by gene targeting and mutants for the genes CG9344, CG15649, CG15650, and ND-B14.7 using the CRISPR/Cas9 system. We determined the lethality period during development for most isolated mutants. In total, we analysed alleles from nine different genes from the 57B region of Drosophila, which could now be used to further explore the functions of the corresponding genes in the future.
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Affiliation(s)
- Eva Louise Steinmetz
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
- Zoology & Physiology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building B2.1, D-66123 Saarbrücken, Germany
| | - Sandra Noh
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Christine Klöppel
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Martin F. Fuhr
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Nicole Bach
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Mona Evelyn Raffael
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Kirsten Hildebrandt
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Fabienne Wittling
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarland University, Building E8.1, D-66123 Saarbrücken, Germany
| | - Doris Jann
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
- Medical Biochemistry & Molecular Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 45.2, D-66421 Homburg, Germany
| | - Uwe Walldorf
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
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Pino MG, Rich KA, Hall NJ, Jones ML, Fox A, Musier-Forsyth K, Kolb SJ. Heterogeneous splicing patterns resulting from KIF5A variants associated with amyotrophic lateral sclerosis. Hum Mol Genet 2023; 32:3166-3180. [PMID: 37593923 DOI: 10.1093/hmg/ddad134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/28/2023] [Accepted: 08/03/2023] [Indexed: 08/19/2023] Open
Abstract
Single-nucleotide variants (SNVs) in the gene encoding Kinesin Family Member 5A (KIF5A), a neuronal motor protein involved in anterograde transport along microtubules, have been associated with amyotrophic lateral sclerosis (ALS). ALS is a rapidly progressive and fatal neurodegenerative disease that primarily affects the motor neurons. Numerous ALS-associated KIF5A SNVs are clustered near the splice-site junctions of the penultimate exon 27 and are predicted to alter the carboxy-terminal (C-term) cargo-binding domain of KIF5A. Mis-splicing of exon 27, resulting in exon exclusion, is proposed to be the mechanism by which these SNVs cause ALS. Whether all SNVs proximal to exon 27 result in exon exclusion is unclear. To address this question, we designed an in vitro minigene splicing assay in human embryonic kidney 293 cells, which revealed heterogeneous site-specific effects on splicing: only 5' splice-site (5'ss) SNVs resulted in exon skipping. We also quantified splicing in select clustered, regularly interspaced, short palindromic repeats-edited human stem cells, differentiated to motor neurons, and in neuronal tissues from a 5'ss SNV knock-in mouse, which showed the same result. Moreover, the survival of representative 3' splice site, 5'ss, and truncated C-term variant KIF5A (v-KIF5A) motor neurons was severely reduced compared with wild-type motor neurons, and overt morphological changes were apparent. While the total KIF5A mRNA levels were comparable across the cell lines, the total KIF5A protein levels were decreased for v-KIF5A lines, suggesting an impairment of protein synthesis or stability. Thus, despite the heterogeneous effect on ribonucleic acid splicing, KIF5A SNVs similarly reduce the availability of the KIF5A protein, leading to axonal transport defects and motor neuron pathology.
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Affiliation(s)
- Megan G Pino
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States
- Department of Biological Chemistry & Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
| | - Kelly A Rich
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
| | - Nicholas J Hall
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States
| | - Meredith L Jones
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
| | - Ashley Fox
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
| | - Karin Musier-Forsyth
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States
- Department of Chemistry & Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
| | - Stephen J Kolb
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States
- Department of Biological Chemistry & Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, United States
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10
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Rele CP, Sandlin KM, Leung W, Reed LK. Manual annotation of Drosophila genes: a Genomics Education Partnership protocol. F1000Res 2023; 11:1579. [PMID: 37854289 PMCID: PMC10579860 DOI: 10.12688/f1000research.126839.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/26/2023] [Indexed: 10/20/2023] Open
Abstract
Annotating the genomes of multiple species allows us to analyze the evolution of their genes. While many eukaryotic genome assemblies already include computational gene predictions, these predictions can benefit from review and refinement through manual gene annotation. The Genomics Education Partnership (GEP; https://thegep.org/) developed a structural annotation protocol for protein-coding genes that enables undergraduate student and faculty researchers to create high-quality gene annotations that can be utilized in subsequent scientific investigations. For example, this protocol has been utilized by the GEP faculty to engage undergraduate students in the comparative annotation of genes involved in the insulin signaling pathway in 27 Drosophila species, using D. melanogaster as the reference genome. Students construct gene models using multiple lines of computational and empirical evidence including expression data (e.g., RNA-Seq), sequence similarity (e.g., BLAST and multiple sequence alignment), and computational gene predictions. Quality control measures require each gene be annotated by at least two students working independently, followed by reconciliation of the submitted gene models by a more experienced student. This article provides an overview of the annotation protocol and describes how discrepancies in student submitted gene models are resolved to produce a final, high-quality gene set suitable for subsequent analyses. The protocol can be adapted to other scientific questions (e.g., expansion of the Drosophila Muller F element) and species (e.g., parasitoid wasps) to provide additional opportunities for undergraduate students to participate in genomics research. These student annotation efforts can substantially improve the quality of gene annotations in publicly available genomic databases.
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Affiliation(s)
- Chinmay P. Rele
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, 35487, USA
| | - Katie M. Sandlin
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, 35487, USA
| | - Wilson Leung
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, 63130, USA
| | - Laura K. Reed
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, 35487, USA
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11
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Azambuja M, Nogaroto V, Moreira-Filho O, Vicari MR. U2 and U4 snDNA Comparative Chromosomal Mapping in the Neotropical Fish Genera Apareiodon and Parodon (Characiformes: Parodontidae). Zebrafish 2023; 20:221-228. [PMID: 37797225 DOI: 10.1089/zeb.2023.0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023] Open
Abstract
Small nuclear DNA (snDNA) are valuable cytogenetic markers for comparative studies in chromosome evolution because different distribution patterns were found among species. Parodontidae, a Neotropical fish family, is known to have female heterogametic sex chromosome systems in some species. The U2 and U4 snDNA sites have been found to be involved in Z and W chromosome differentiation in Apareiodon sp., Apareiodon affinis, and Parodon hilarii. However, few studies have evaluated snDNA sites as propulsors of chromosome diversification among closely related fish species. In this study, we investigated the distribution of U2 and U4 snDNA clusters in the chromosomes of 10 populations/species belonging to Apareiodon and Parodon, aiming to identify chromosomal homeologies or diversification. In situ localization data revealed a submetacentric pair carrying the U2 snDNA site among the populations/species analyzed. Furthermore, all studied species demonstrated homeology in the location of U4 snDNA cluster in the proximal region of metacentric pair 1, besides an additional signal showing up with a divergence in Apareiodon. Comparative chromosomal mapping of U4 snDNA also helped to reinforce the proposal of the ZZ/ZW1W2 sex chromosome system origin in an A. affinis population. According to cytogenetic data, the study corroborates the diversification in Parodontidae paired species with uncertain taxonomy.
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Affiliation(s)
- Matheus Azambuja
- Programa de Pós-Graduação em Genética, Universidade Federal do Paraná, Curitiba, Brazil
| | - Viviane Nogaroto
- Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Ponta Grossa, Brazil
| | - Orlando Moreira-Filho
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Marcelo Ricardo Vicari
- Programa de Pós-Graduação em Genética, Universidade Federal do Paraná, Curitiba, Brazil
- Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Ponta Grossa, Brazil
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12
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Cheng W, Hong C, Zeng F, Liu N, Gao H. Sequence variations affect the 5' splice site selection of plant introns. PLANT PHYSIOLOGY 2023; 193:1281-1296. [PMID: 37394939 DOI: 10.1093/plphys/kiad375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 05/31/2023] [Accepted: 06/04/2023] [Indexed: 07/04/2023]
Abstract
Introns are noncoding sequences spliced out of pre-mRNAs by the spliceosome to produce mature mRNAs. The 5' ends of introns mostly begin with GU and have a conserved sequence motif of AG/GUAAGU that could base-pair with the core sequence of U1 snRNA of the spliceosome. Intriguingly, ∼ 1% of introns in various eukaryotic species begin with GC. This occurrence could cause misannotation of genes; however, the underlying splicing mechanism is unclear. We analyzed the sequences around the intron 5' splice site (ss) in Arabidopsis (Arabidopsis thaliana) and found sequences at the GC intron ss are much more stringent than those of GT introns. Mutational analysis at various positions of the intron 5' ss revealed that although mutations impair base pairing, different mutations at the same site can have different effects, suggesting that steric hindrance also affects splicing. Moreover, mutations of 5' ss often activate a hidden ss nearby. Our data suggest that the 5' ss is selected via a competition between the major ss and the nearby minor ss. This work not only provides insights into the splicing mechanism of intron 5' ss but also improves the accuracy of gene annotation and the study of the evolution of intron 5' ss.
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Affiliation(s)
- Wenzhen Cheng
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Conghao Hong
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Fang Zeng
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Nan Liu
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Hongbo Gao
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
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13
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Wang R, Helbig I, Edmondson AC, Lin L, Xing Y. Splicing defects in rare diseases: transcriptomics and machine learning strategies towards genetic diagnosis. Brief Bioinform 2023; 24:bbad284. [PMID: 37580177 PMCID: PMC10516351 DOI: 10.1093/bib/bbad284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 07/10/2023] [Accepted: 07/20/2023] [Indexed: 08/16/2023] Open
Abstract
Genomic variants affecting pre-messenger RNA splicing and its regulation are known to underlie many rare genetic diseases. However, common workflows for genetic diagnosis and clinical variant interpretation frequently overlook splice-altering variants. To better serve patient populations and advance biomedical knowledge, it has become increasingly important to develop and refine approaches for detecting and interpreting pathogenic splicing variants. In this review, we will summarize a few recent developments and challenges in using RNA sequencing technologies for rare disease investigation. Moreover, we will discuss how recent computational splicing prediction tools have emerged as complementary approaches for revealing disease-causing variants underlying splicing defects. We speculate that continuous improvements to sequencing technologies and predictive modeling will not only expand our understanding of splicing regulation but also bring us closer to filling the diagnostic gap for rare disease patients.
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Affiliation(s)
- Robert Wang
- Center for Computational and Genomic Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ingo Helbig
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew C Edmondson
- Center for Computational and Genomic Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pediatrics, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Lan Lin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yi Xing
- Center for Computational and Genomic Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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14
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Girardini KN, Olthof AM, Kanadia RN. Introns: the "dark matter" of the eukaryotic genome. Front Genet 2023; 14:1150212. [PMID: 37260773 PMCID: PMC10228655 DOI: 10.3389/fgene.2023.1150212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/28/2023] [Indexed: 06/02/2023] Open
Abstract
The emergence of introns was a significant evolutionary leap that is a major distinguishing feature between prokaryotic and eukaryotic genomes. While historically introns were regarded merely as the sequences that are removed to produce spliced transcripts encoding functional products, increasingly data suggests that introns play important roles in the regulation of gene expression. Here, we use an intron-centric lens to review the role of introns in eukaryotic gene expression. First, we focus on intron architecture and how it may influence mechanisms of splicing. Second, we focus on the implications of spliceosomal snRNAs and their variants on intron splicing. Finally, we discuss how the presence of introns and the need to splice them influences transcription regulation. Despite the abundance of introns in the eukaryotic genome and their emerging role regulating gene expression, a lot remains unexplored. Therefore, here we refer to introns as the "dark matter" of the eukaryotic genome and discuss some of the outstanding questions in the field.
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Affiliation(s)
- Kaitlin N. Girardini
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
| | - Anouk M. Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Rahul N. Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, United States
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15
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Funakoshi Y, Sugihara Y, Uneda A, Nakashima T, Suzuki H. Recent advances in the molecular understanding of medulloblastoma. Cancer Sci 2023; 114:741-749. [PMID: 36520034 PMCID: PMC9986075 DOI: 10.1111/cas.15691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/25/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
Medulloblastoma is the most common pediatric malignant brain tumor composed of four molecular subgroups. Recent intensive genomics has greatly contributed to our understanding of medulloblastoma pathogenesis. Sequencing studies identified novel mutations involved in the cyclic AMP-dependent pathway or RNA processing in the Sonic Hedgehog (SHH) subgroup, and core-binding factor subunit alpha (CBFA) complex in the group 4 subgroup. Likewise, single-cell sequencing provided detailed insights into the cell of origin associated with brain development. In this review, we will summarize recent findings by sequencing analyses for medulloblastoma.
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Affiliation(s)
- Yusuke Funakoshi
- Division of Brain Tumor Translational Research, National Cancer Center Research Institute, Chuo-ku, Japan
| | - Yuriko Sugihara
- Division of Brain Tumor Translational Research, National Cancer Center Research Institute, Chuo-ku, Japan
| | - Atsuhito Uneda
- Division of Brain Tumor Translational Research, National Cancer Center Research Institute, Chuo-ku, Japan
| | - Takuma Nakashima
- Division of Brain Tumor Translational Research, National Cancer Center Research Institute, Chuo-ku, Japan
| | - Hiromichi Suzuki
- Division of Brain Tumor Translational Research, National Cancer Center Research Institute, Chuo-ku, Japan
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16
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Maxeiner S, Krasteva-Christ G, Althaus M. Pitfalls of using sequence databases for heterologous expression studies - a technical review. J Physiol 2023; 601:1611-1623. [PMID: 36762618 DOI: 10.1113/jp284066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
Abstract
Synthesis of DNA fragments based on gene sequences that are available in public resources has become an efficient and affordable method that has gradually replaced traditional cloning efforts such as PCR cloning from cDNA. However, database entries based on genome sequencing results are prone to errors which can lead to false sequence information and, ultimately, errors in functional characterisation of proteins such as ion channels and transporters in heterologous expression systems. We have identified five common problems that repeatedly appear in public resources: (1) Not every gene has yet been annotated; (2) not all gene annotations are necessarily correct; (3) transcripts may contain automated corrections; (4) there are mismatches between gene, mRNA and protein sequences; and (5) splicing patterns often lack experimental validation. This technical review highlights and provides a strategy to bypass these issues in order to avoid critical mistakes that could impact future studies of any gene/protein of interest in heterologous expression systems.
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Affiliation(s)
- Stephan Maxeiner
- Institute for Anatomy and Cell Biology, Saarland University, Homburg, Germany
| | | | - Mike Althaus
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, Rheinbach, Germany
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17
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Ma SH, He GQ, Navarro-Payá D, Santiago A, Cheng YZ, Jiao JB, Li HJ, Zuo DD, Sun HT, Pei MS, Yu YH, Matus JT, Guo DL. Global analysis of alternative splicing events based on long- and short-read RNA sequencing during grape berry development. Gene 2023; 852:147056. [PMID: 36414171 DOI: 10.1016/j.gene.2022.147056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 11/09/2022] [Accepted: 11/14/2022] [Indexed: 11/21/2022]
Affiliation(s)
- Shuai-Hui Ma
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - Guang-Qi He
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - David Navarro-Payá
- Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, Paterna, Spain
| | - Antonio Santiago
- Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, Paterna, Spain
| | - Yi-Zhe Cheng
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - Jia-Bing Jiao
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - Hui-Jie Li
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - Ding-Ding Zuo
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - Hao-Ting Sun
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - Mao-Song Pei
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - Yi-He Yu
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China
| | - José Tomás Matus
- Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, Paterna, Spain
| | - Da-Long Guo
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang 471023, China; Henan Engineering Technology Research Center of Quality Regulation of Horticultural Plants, Luoyang 471023, China.
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18
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Gao Y, Wang F, Wang R, Kutschera E, Xu Y, Xie S, Wang Y, Kadash-Edmondson KE, Lin L, Xing Y. ESPRESSO: Robust discovery and quantification of transcript isoforms from error-prone long-read RNA-seq data. SCIENCE ADVANCES 2023; 9:eabq5072. [PMID: 36662851 PMCID: PMC9858503 DOI: 10.1126/sciadv.abq5072] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 12/16/2022] [Indexed: 05/20/2023]
Abstract
Long-read RNA sequencing (RNA-seq) holds great potential for characterizing transcriptome variation and full-length transcript isoforms, but the relatively high error rate of current long-read sequencing platforms poses a major challenge. We present ESPRESSO, a computational tool for robust discovery and quantification of transcript isoforms from error-prone long reads. ESPRESSO jointly considers alignments of all long reads aligned to a gene and uses error profiles of individual reads to improve the identification of splice junctions and the discovery of their corresponding transcript isoforms. On both a synthetic spike-in RNA sample and human RNA samples, ESPRESSO outperforms multiple contemporary tools in not only transcript isoform discovery but also transcript isoform quantification. In total, we generated and analyzed ~1.1 billion nanopore RNA-seq reads covering 30 human tissue samples and three human cell lines. ESPRESSO and its companion dataset provide a useful resource for studying the RNA repertoire of eukaryotic transcriptomes.
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Affiliation(s)
- Yuan Gao
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Feng Wang
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Robert Wang
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eric Kutschera
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yang Xu
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephan Xie
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yuanyuan Wang
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kathryn E. Kadash-Edmondson
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Lan Lin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yi Xing
- Center for Computational and Genomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biomedical and Health Informatics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
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19
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Li H. Protein-to-genome alignment with miniprot. Bioinformatics 2023; 39:btad014. [PMID: 36648328 PMCID: PMC9869432 DOI: 10.1093/bioinformatics/btad014] [Citation(s) in RCA: 52] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/25/2022] [Accepted: 01/16/2023] [Indexed: 01/18/2023] Open
Abstract
MOTIVATION Protein-to-genome alignment is critical to annotating genes in non-model organisms. While there are a few tools for this purpose, all of them were developed over 10 years ago and did not incorporate the latest advances in alignment algorithms. They are inefficient and could not keep up with the rapid production of new genomes and quickly growing protein databases. RESULTS Here, we describe miniprot, a new aligner for mapping protein sequences to a complete genome. Miniprot integrates recent techniques such as k-mer sketch and vectorized dynamic programming. It is tens of times faster than existing tools while achieving comparable accuracy on real data. AVAILABILITY AND IMPLEMENTATION https://github.com/lh3/miniport.
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Affiliation(s)
- Heng Li
- Department of Data Sciences, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
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20
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Ding Z, Meng YR, Fan YJ, Xu YZ. Roles of minor spliceosome in intron recognition and the convergence with the better understood major spliceosome. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1761. [PMID: 36056453 DOI: 10.1002/wrna.1761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 06/06/2022] [Accepted: 08/06/2022] [Indexed: 01/31/2023]
Abstract
Catalyzed by spliceosomes in the nucleus, RNA splicing removes intronic sequences from precursor RNAs in eukaryotes to generate mature RNA, which also significantly increases proteome complexity and fine-tunes gene expression. Most metazoans have two coexisting spliceosomes; the major spliceosome, which removes >99.5% of introns, and the minor spliceosome, which removes far fewer introns (only 770 at present have been predicted in the human genome). Both spliceosomes are large and dynamic machineries, each consisting of five small nuclear RNAs (snRNAs) and more than 100 proteins. However, the dynamic assembly, catalysis, and protein composition of the minor spliceosome are still poorly understood. With different splicing signals, minor introns are rare and usually distributed alone and flanked by major introns in genes, raising questions of how they are recognized by the minor spliceosome and how their processing deals with the splicing of neighboring major introns. Due to large numbers of introns and close similarities between the two machinery, cooperative, and competitive recognition by the two spliceosomes has been investigated. Functionally, many minor-intron-containing genes are evolutionarily conserved and essential. Mutations in the minor spliceosome exhibit a variety of developmental defects in plants and animals and are linked to numerous human diseases. Here, we review recent progress in the understanding of minor splicing, compare currently known components of the two spliceosomes, survey minor introns in a wide range of organisms, discuss cooperation and competition of the two spliceosomes in splicing of minor-intron-containing genes, and contributions of minor splicing mutations in development and diseases. This article is categorized under: RNA Processing > Processing of Small RNAs RNA Processing > Splicing Mechanisms RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.
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Affiliation(s)
- Zhan Ding
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China.,Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yan-Ran Meng
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
| | - Yu-Jie Fan
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
| | - Yong-Zhen Xu
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
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21
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Logeswaran D, Li Y, Akhter K, Podlevsky JD, Olson TL, Forsberg K, Chen JJL. Biogenesis of telomerase RNA from a protein-coding mRNA precursor. Proc Natl Acad Sci U S A 2022; 119:e2204636119. [PMID: 36197996 PMCID: PMC9564094 DOI: 10.1073/pnas.2204636119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 08/29/2022] [Indexed: 11/19/2022] Open
Abstract
Telomerase is a eukaryotic ribonucleoprotein (RNP) enzyme that adds DNA repeats onto chromosome ends to maintain genomic stability and confer cellular immortality in cancer and stem cells. The telomerase RNA (TER) component is essential for telomerase catalytic activity and provides the template for telomeric DNA synthesis. The biogenesis of TERs is extremely divergent across eukaryotic kingdoms, employing distinct types of transcription machinery and processing pathways. In ciliates and plants, TERs are transcribed by RNA polymerase III (Pol III), while animal and ascomycete fungal TERs are transcribed by RNA Pol II and share biogenesis pathways with small nucleolar RNA (snoRNA) and small nuclear RNA (snRNA), respectively. Here, we report an unprecedented messenger RNA (mRNA)-derived biogenesis pathway for the 1,291 nucleotide TER from the basidiomycete fungus Ustilago maydis. The U. maydis TER (UmTER) contains a 5'-monophosphate, distinct from the 5' 2,2,7-trimethylguanosine (TMG) cap common to animal and ascomycete fungal TERs. The mature UmTER is processed from the 3'-untranslated region (3'-UTR) of a larger RNA precursor that possesses characteristics of mRNA including a 5' 7-methyl-guanosine (m7G) cap, alternative splicing of introns, and a poly(A) tail. Moreover, this mRNA transcript encodes a protein called Early meiotic induction protein 1 (Emi1) that is conserved across dikaryotic fungi. A recombinant UmTER precursor expressed from an mRNA promoter is processed correctly to yield mature UmTER, confirming an mRNA-processing pathway for producing TER. Our findings expand the plethora of TER biogenesis mechanisms and demonstrate a pathway for producing a functional long noncoding RNA from a protein-coding mRNA precursor.
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Affiliation(s)
| | - Yang Li
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281
| | - Khadiza Akhter
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281
| | | | - Tamara L. Olson
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281
| | | | - Julian J.-L. Chen
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281
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22
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Zhang R, Kuo R, Coulter M, Calixto CPG, Entizne JC, Guo W, Marquez Y, Milne L, Riegler S, Matsui A, Tanaka M, Harvey S, Gao Y, Wießner-Kroh T, Paniagua A, Crespi M, Denby K, Hur AB, Huq E, Jantsch M, Jarmolowski A, Koester T, Laubinger S, Li QQ, Gu L, Seki M, Staiger D, Sunkar R, Szweykowska-Kulinska Z, Tu SL, Wachter A, Waugh R, Xiong L, Zhang XN, Conesa A, Reddy ASN, Barta A, Kalyna M, Brown JWS. A high-resolution single-molecule sequencing-based Arabidopsis transcriptome using novel methods of Iso-seq analysis. Genome Biol 2022; 23:149. [PMID: 35799267 PMCID: PMC9264592 DOI: 10.1186/s13059-022-02711-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 06/15/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Accurate and comprehensive annotation of transcript sequences is essential for transcript quantification and differential gene and transcript expression analysis. Single-molecule long-read sequencing technologies provide improved integrity of transcript structures including alternative splicing, and transcription start and polyadenylation sites. However, accuracy is significantly affected by sequencing errors, mRNA degradation, or incomplete cDNA synthesis. RESULTS We present a new and comprehensive Arabidopsis thaliana Reference Transcript Dataset 3 (AtRTD3). AtRTD3 contains over 169,000 transcripts-twice that of the best current Arabidopsis transcriptome and including over 1500 novel genes. Seventy-eight percent of transcripts are from Iso-seq with accurately defined splice junctions and transcription start and end sites. We develop novel methods to determine splice junctions and transcription start and end sites accurately. Mismatch profiles around splice junctions provide a powerful feature to distinguish correct splice junctions and remove false splice junctions. Stratified approaches identify high-confidence transcription start and end sites and remove fragmentary transcripts due to degradation. AtRTD3 is a major improvement over existing transcriptomes as demonstrated by analysis of an Arabidopsis cold response RNA-seq time-series. AtRTD3 provides higher resolution of transcript expression profiling and identifies cold-induced differential transcription start and polyadenylation site usage. CONCLUSIONS AtRTD3 is the most comprehensive Arabidopsis transcriptome currently. It improves the precision of differential gene and transcript expression, differential alternative splicing, and transcription start/end site usage analysis from RNA-seq data. The novel methods for identifying accurate splice junctions and transcription start/end sites are widely applicable and will improve single-molecule sequencing analysis from any species.
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Affiliation(s)
- Runxuan Zhang
- Information and Computational Sciences, James Hutton Institute, Dundee, DD2 5DA, Scotland, UK.
| | - Richard Kuo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Max Coulter
- Plant Sciences Division, School of Life Sciences, University of Dundee at The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK
| | - Cristiane P G Calixto
- Plant Sciences Division, School of Life Sciences, University of Dundee at The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK
- Present address: Institute of Biosciences, University of São Paulo, São Paulo, 05508-090, Brazil
| | - Juan Carlos Entizne
- Plant Sciences Division, School of Life Sciences, University of Dundee at The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK
| | - Wenbin Guo
- Information and Computational Sciences, James Hutton Institute, Dundee, DD2 5DA, Scotland, UK
| | - Yamile Marquez
- Centre for Genomic Regulation, C/ Dr. Aiguader 88, 08003, Barcelona, Spain
| | - Linda Milne
- Information and Computational Sciences, James Hutton Institute, Dundee, DD2 5DA, Scotland, UK
| | - Stefan Riegler
- Institute of Molecular Plant Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, 1190, Vienna, Austria
- Present address: Institute of Science and Technology Austria, Am Campus 1, 3400, Klosterneuburg, Austria
| | - Akihiro Matsui
- Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Maho Tanaka
- Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Sarah Harvey
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York Wentworth Way, York, YO10 5DD, UK
| | - Yubang Gao
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Theresa Wießner-Kroh
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Alejandro Paniagua
- Institute for Integrative Systems Biology (CSIC-UV), Spanish National Research Council, Paterna, Valencia, Spain
| | - Martin Crespi
- French National Centre for Scientific Research | CNRS INRAE-Universities of Paris Saclay and Paris, Institute of Plant Sciences Paris Saclay IPS2, Rue de Noetzlin, 91192, Gif sur Yvette, France
| | - Katherine Denby
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York Wentworth Way, York, YO10 5DD, UK
| | - Asa Ben Hur
- Department of Computer Science, Colorado State University, 1873 Campus Delivery, Fort Collins, CO, 80523-1873, USA
| | - Enamul Huq
- Department of Molecular Biosciences, University of Texas at Austin, 100 East 24th St., Austin, TX, 78712-1095, USA
| | - Michael Jantsch
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17 A-1090, Vienna, Austria
| | - Artur Jarmolowski
- Department of Gene Expression, Adam Mickiewicz University, Poznań, Poland
| | - Tino Koester
- RNA Biology and Molecular Physiology, Faculty for Biology, Bielefeld University, Universitaetsstrasse 25, 33615, Bielefeld, Germany
| | - Sascha Laubinger
- Institut für Biologie und Umweltwissenschaften (IBU), Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky-Str. 9-11, 26111, Oldenburg, Germany
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Qingshun Quinn Li
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, 91766, USA
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, Fujian, China
| | - Lianfeng Gu
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Motoaki Seki
- Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Dorothee Staiger
- RNA Biology and Molecular Physiology, Faculty for Biology, Bielefeld University, Universitaetsstrasse 25, 33615, Bielefeld, Germany
| | - Ramanjulu Sunkar
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | | | - Shih-Long Tu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Andreas Wachter
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
- Present address: Institute for Molecular Physiology, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany
| | - Robbie Waugh
- Cell and Molecular Sciences, James Hutton Institute, Dundee, DD2 5DA, Scotland, UK
| | - Liming Xiong
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Xiao-Ning Zhang
- Biology Department, School of Arts and Sciences, St. Bonaventure University, 3261 West State Road, St. Bonaventure, NY, 14778, USA
| | - Ana Conesa
- Institute for Integrative Systems Biology (CSIC-UV), Spanish National Research Council, Paterna, Valencia, Spain
| | - Anireddy S N Reddy
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Andrea Barta
- Max F. Perutz Laboratories, Medical University of Vienna, Center of Medical Biochemistry, Dr.-Bohr-Gasse 9/3, A-1030, Vienna, Austria
| | - Maria Kalyna
- Institute of Molecular Plant Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, 1190, Vienna, Austria
| | - John W S Brown
- Plant Sciences Division, School of Life Sciences, University of Dundee at The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK
- Cell and Molecular Sciences, James Hutton Institute, Dundee, DD2 5DA, Scotland, UK
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23
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Azambuja M, Orane Schemberger M, Nogaroto V, Moreira-Filho O, Martins C, Ricardo Vicari M. Major and minor U small nuclear RNAs genes characterization in a neotropical fish genome: Chromosomal remodeling and repeat units dispersion in Parodontidae. Gene 2022; 826:146459. [PMID: 35358649 DOI: 10.1016/j.gene.2022.146459] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/15/2022] [Accepted: 03/25/2022] [Indexed: 11/29/2022]
Abstract
In association with many proteins, small nuclear RNAs (snRNAs) organize the spliceosomes that play a significant role in processing precursor mRNAs during gene expression. According to snRNAs genic arrangements, two kinds of spliceosomes (major and minor) can be organized into eukaryotic cells. Although in situ localization of U1 and U2 snDNAs have been performed in fish karyotypes, studies with genomic characterization and functionality of U snRNAs integrated into chromosomal changes on Teleostei are still scarce. This study aimed to achieve a genomic characterization of the U snRNAs genes in Apareiodon sp. (2n = 54, ZZ/ZW), apply these data to recognize functional/defective copies, and map chromosomal changes involving snDNAs in Parodontidae species karyotype diversification. Nine snRNA multigene families (U1, U2, U4, U5, U6, U11, U12, U4atac and U6atac) arranged in putatively functional copies in the genome were analyzed. Proximal Sequence Elements (PSE) and TATA-box promoters occurrence, besides an entire transcribed region and conserved secondary structures, qualify them for spliceosome activity. In addition, several defective copies or pseudogenes were identified for the snRNAs that make up the major spliceosome. In situ localization of snDNAs in five species of Parodontidae demonstrated that U1, U2, and U4 snDNAs were involved in chromosomal location changes or units dispersion. The U snRNAs defective/pseudogenes units dispersion could be favored by the probable occurrence of active retrotransposition enzymes in the Apareiodon genome. The U2 and U4 snDNAs sites were involved in independent events in the differentiation of sex chromosomes among Parodontidae lineages. The study characterized U snRNA genes that compose major and minor spliceosomes in the Apareiodon sp. genome and proposes that their defective copies trigger chromosome differentiation and diversification events in Parodontidae.
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Affiliation(s)
- Matheus Azambuja
- Programa de Pós-Graduação em Genética, Universidade Federal do Paraná, Centro Politécnico, Avenida Coronel Francisco H. dos Santos, 100, 81531-990 Curitiba, Paraná, Brazil.
| | - Michelle Orane Schemberger
- Programa de Pós-Graduação em Genética, Universidade Federal do Paraná, Centro Politécnico, Avenida Coronel Francisco H. dos Santos, 100, 81531-990 Curitiba, Paraná, Brazil.
| | - Viviane Nogaroto
- Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
| | - Orlando Moreira-Filho
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, Rodovia Washington Luís, Km 235, 13565-905 São Carlos, São Paulo, Brazil.
| | - Cesar Martins
- Departamento de Morfologia, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Distrito de Rubião Júnior, s/n, 18618-689 Botucatu, São Paulo, Brazil.
| | - Marcelo Ricardo Vicari
- Programa de Pós-Graduação em Genética, Universidade Federal do Paraná, Centro Politécnico, Avenida Coronel Francisco H. dos Santos, 100, 81531-990 Curitiba, Paraná, Brazil; Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
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24
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Georgakopoulos-Soares I, Parada GE, Wong HY, Medhi R, Furlan G, Munita R, Miska EA, Kwok CK, Hemberg M. Alternative splicing modulation by G-quadruplexes. Nat Commun 2022; 13:2404. [PMID: 35504902 PMCID: PMC9065059 DOI: 10.1038/s41467-022-30071-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 03/30/2022] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing is central to metazoan gene regulation, but the regulatory mechanisms are incompletely understood. Here, we show that G-quadruplex (G4) motifs are enriched ~3-fold near splice junctions. The importance of G4s in RNA is emphasised by a higher enrichment for the non-template strand. RNA-seq data from mouse and human neurons reveals an enrichment of G4s at exons that were skipped following depolarisation induced by potassium chloride. We validate the formation of stable RNA G4s for three candidate splice sites by circular dichroism spectroscopy, UV-melting and fluorescence measurements. Moreover, we find that sQTLs are enriched at G4s, and a minigene experiment provides further support for their role in promoting exon inclusion. Analysis of >1,800 high-throughput experiments reveals multiple RNA binding proteins associated with G4s. Finally, exploration of G4 motifs across eleven species shows strong enrichment at splice sites in mammals and birds, suggesting an evolutionary conserved splice regulatory mechanism. Here the authors shows that G-quadruplexes, non-canonical DNA/RNA structures, can have a direct impact on alternative splicing and that binding of splicing regulators is affected by their presence.
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Affiliation(s)
- Ilias Georgakopoulos-Soares
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK.,Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Guillermo E Parada
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK.,Wellcome Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.,Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.,Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5A 1A8, Canada
| | - Hei Yuen Wong
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Ragini Medhi
- Wellcome Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.,Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Giulia Furlan
- Wellcome Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.,Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Roberto Munita
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, Lund, Sweden
| | - Eric A Miska
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK.,Wellcome Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.,Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Chun Kit Kwok
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.,Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China
| | - Martin Hemberg
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK. .,Wellcome Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK. .,Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, 02115, USA.
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25
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Li S, Zhang S, Huang M, Hu H, Xie Y. U1RNP/lncRNA/Transcription Cycle Axis Promotes Tumorigenesis of Hepatocellular Carcinoma. Diagnostics (Basel) 2022; 12:1133. [PMID: 35626291 PMCID: PMC9139874 DOI: 10.3390/diagnostics12051133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/25/2022] [Accepted: 04/30/2022] [Indexed: 02/01/2023] Open
Abstract
As a component of the spliceosome, U1 small nuclear ribonucleoproteins (U1RNPs) play critical roles in RNA splicing, and recent studies have shown that U1RNPs could recruit long non-coding RNAs (lncRNAs) to chromatin which are involved in cancer development. However, the interplay of U1 snRNP, lncRNAs and downstream genes and signaling pathways are insufficiently understood in hepatocellular carcinoma (HCC). The expression of U1RNPs was found to be significantly higher in tumors than normal tissues in liver hepatocellular carcinomas of The Cancer Genome Atlas (TCGA-LIHC) dataset. LncRNAs with potential U1-binding sites (termed U1-lncRNAs) were found to be mostly located in the nucleus and their expression was higher in tumor than in normal tissues Bioinformatic analysis indicated that U1-lncRNAs worked with RNA-binding proteins and regulated the transcription cycle in HCC. A U1-lncRNA risk model was constructed using a TCGA dataset, and the AUCs of this risk model to predict 1-, 3- and 5-year overall survival were 0.82, 0.84 and 0.8, respectively. Furthermore, silencing of the small nuclear ribonucleoprotein D2 polypeptide (SNRPD2) resulted in impaired proliferation, G1/M cell cycle arrest and downregulation of transcription-cycle-related genes in HCC cell lines. Taken together, these results indicate that U1RNPs interact with lncRNAs and promote the transcription cycle process in HCC, which suggests that these could be novel biomarkers in the clinical management of HCC.
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Affiliation(s)
- Shun Li
- Department of Oncology, The First Affiliated Hospital, Sun Yat-sen University, No 58, Zhongshan Er Road, Guangzhou 510080, China; (S.L.); (M.H.)
| | - Shuaiyin Zhang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No 58, Zhongshan Er Road, Guangzhou 510080, China; (S.Z.); (H.H.)
| | - Mingle Huang
- Department of Oncology, The First Affiliated Hospital, Sun Yat-sen University, No 58, Zhongshan Er Road, Guangzhou 510080, China; (S.L.); (M.H.)
| | - Huanjing Hu
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No 58, Zhongshan Er Road, Guangzhou 510080, China; (S.Z.); (H.H.)
| | - Yubin Xie
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No 58, Zhongshan Er Road, Guangzhou 510080, China; (S.Z.); (H.H.)
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26
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Szewczyk MM, Luciani GM, Vu V, Murison A, Dilworth D, Barghout SH, Lupien M, Arrowsmith CH, Minden MD, Barsyte-Lovejoy D. PRMT5 regulates ATF4 transcript splicing and oxidative stress response. Redox Biol 2022; 51:102282. [PMID: 35305370 PMCID: PMC8933703 DOI: 10.1016/j.redox.2022.102282] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/18/2022] [Accepted: 03/08/2022] [Indexed: 02/07/2023] Open
Abstract
Protein methyltransferase 5 (PRMT5) symmetrically dimethylates arginine residues leading to regulation of transcription and splicing programs. Although PRMT5 has emerged as an attractive oncology target, the molecular determinants of PRMT5 dependency in cancer remain incompletely understood. Our transcriptomic analysis identified PRMT5 regulation of the activating transcription factor 4 (ATF4) pathway in acute myelogenous leukemia (AML). PRMT5 inhibition resulted in the expression of unstable, intron-retaining ATF4 mRNA that is detained in the nucleus. Concurrently, the decrease in the spliced cytoplasmic transcript of ATF4 led to lower levels of ATF4 protein and downregulation of ATF4 target genes. Upon loss of functional PRMT5, cells with low ATF4 displayed increased oxidative stress, growth arrest, and cellular senescence. Interestingly, leukemia cells with EVI1 oncogene overexpression demonstrated dependence on PRMT5 function. EVI1 and ATF4 regulated gene signatures were inversely correlated. We show that EVI1-high AML cells have reduced ATF4 levels, elevated baseline reactive oxygen species and increased sensitivity to PRMT5 inhibition. Thus, EVI1-high cells demonstrate dependence on PRMT5 function and regulation of oxidative stress response. Overall, our findings identify the PRMT5-ATF4 axis to be safeguarding the cellular redox balance that is especially important in high oxidative stress states, such as those that occur with EVI1 overexpression.
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Affiliation(s)
| | - Genna M Luciani
- Department of Medical Biophysics, University of Toronto, Ontario, Canada; Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Victoria Vu
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Ontario, Canada
| | - Alex Murison
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - David Dilworth
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Samir H Barghout
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Mathieu Lupien
- Department of Medical Biophysics, University of Toronto, Ontario, Canada; Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Cheryl H Arrowsmith
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Ontario, Canada; Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Mark D Minden
- Department of Medical Biophysics, University of Toronto, Ontario, Canada; Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
| | - Dalia Barsyte-Lovejoy
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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27
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Pitolli C, Marini A, Sette C, Pagliarini V. Non-Canonical Splicing and Its Implications in Brain Physiology and Cancer. Int J Mol Sci 2022; 23:ijms23052811. [PMID: 35269953 PMCID: PMC8911335 DOI: 10.3390/ijms23052811] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 02/01/2023] Open
Abstract
The advance of experimental and computational techniques has allowed us to highlight the existence of numerous different mechanisms of RNA maturation, which have been so far unknown. Besides canonical splicing, consisting of the removal of introns from pre-mRNA molecules, non-canonical splicing events may occur to further increase the regulatory and coding potential of the human genome. Among these, splicing of microexons, recursive splicing and biogenesis of circular and chimeric RNAs through back-splicing and trans-splicing processes, respectively, all contribute to expanding the repertoire of RNA transcripts with newly acquired regulatory functions. Interestingly, these non-canonical splicing events seem to occur more frequently in the central nervous system, affecting neuronal development and differentiation programs with important implications on brain physiology. Coherently, dysregulation of non-canonical RNA processing events is associated with brain disorders, including brain tumours. Herein, we summarize the current knowledge on molecular and regulatory mechanisms underlying canonical and non-canonical splicing events with particular emphasis on cis-acting elements and trans-acting factors that all together orchestrate splicing catalysis reactions and decisions. Lastly, we review the impact of non-canonical splicing on brain physiology and pathology and how unconventional splicing mechanisms may be targeted or exploited for novel therapeutic strategies in cancer.
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Affiliation(s)
- Consuelo Pitolli
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Alberto Marini
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
- Correspondence:
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28
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Choi S, Cho N, Kim KK. Non-canonical splice junction processing increases the diversity of RBFOX2 splicing isoforms. Int J Biochem Cell Biol 2022; 144:106172. [PMID: 35124219 DOI: 10.1016/j.biocel.2022.106172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 01/23/2022] [Accepted: 02/01/2022] [Indexed: 12/13/2022]
Abstract
The underlying mechanisms of splicing regulation through non-canonical splice junction processing remain largely unknown. Here, we identified two RBFOX2 splicing isoforms by alternative 3' splice site selection of exon 9; the non-canonical splice junction processed RBFOX2 transcript (RBFOX2-N.C.) was expressed by the selection of the 3' splice GG acceptor sequence. The cytoplasmic localization of RBFOX2-C., a canonical splice junction-processed RBFOX2 transcript, was different from that of RBFOX2-N.C., which showed nuclear localization. In addition, we confirmed that RBFOX2-C. showed a significantly stronger localization into stress granules than RBFOX2-N.C. upon sodium arsenite treatment. Next, we investigated the importance of non-canonical 3' splice GG sequence selection of specific cis-regulatory elements using minigene constructs of the RBFOX2 gene. We found that the non-canonical 3' splice GG sequence and suboptimal branch point site adjacent region were critical for RBFOX2-N.C. expression through a non-canonical 3' splice selection. Our results suggest a regulatory mechanism for the non-canonical 3' splice selection in the RBFOX2 gene, providing a basis for studies related to the regulation of alternative pre-mRNA splicing through non-canonical splice junction processing.
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Affiliation(s)
- Sunkyung Choi
- Department of Biochemistry, College of Natural Sciences, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Namjoon Cho
- Department of Biochemistry, College of Natural Sciences, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Kee K Kim
- Department of Biochemistry, College of Natural Sciences, Chungnam National University, Daejeon, 34134, Republic of Korea.
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29
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Parada GE, Hemberg M. Identification and Quantification of Microexons Using Bulk and Single-Cell RNA-Seq Data. Methods Mol Biol 2022; 2537:129-147. [PMID: 35895262 DOI: 10.1007/978-1-0716-2521-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The analysis of RNA-seq has greatly improved the characterization and understanding of the transcriptome. In particular, RNA-seq experiments have extended catalogs of alternative splicing events. However, the analysis of RNAs-seq data for detection and quantification of microexons, extremely short exons of length up to 30 nt, require specialized computational workflows. Here, we describe MicroExonator, a reproducible computational workflow for microexon splicing analysis using bulk or single-cell RNA-seq data.
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Affiliation(s)
- Guillermo E Parada
- Wellcome Sanger Institute, Cambridge, UK
- Donnelly Centre for Cellular and Biomolecular Research and Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Martin Hemberg
- Wellcome Sanger Institute, Cambridge, UK.
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA.
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30
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Shefer K, Boulos A, Gotea V, Arafat M, Ben Chaim Y, Muharram A, Isaac S, Eden A, Sperling J, Elnitski L, Sperling R. A novel role for nucleolin in splice site selection. RNA Biol 2021; 19:333-352. [PMID: 35220879 PMCID: PMC8890436 DOI: 10.1080/15476286.2021.2020455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 12/10/2021] [Indexed: 01/12/2023] Open
Abstract
Latent 5' splice sites, not normally used, are highly abundant in human introns, but are activated under stress and in cancer, generating thousands of nonsense mRNAs. A previously proposed mechanism to suppress latent splicing was shown to be independent of NMD, with a pivotal role for initiator-tRNA independent of protein translation. To further elucidate this mechanism, we searched for nuclear proteins directly bound to initiator-tRNA. Starting with UV-crosslinking, we identified nucleolin (NCL) interacting directly and specifically with initiator-tRNA in the nucleus, but not in the cytoplasm. Next, we show the association of ini-tRNA and NCL with pre-mRNA. We further show that recovery of suppression of latent splicing by initiator-tRNA complementation is NCL dependent. Finally, upon nucleolin knockdown we show activation of latent splicing in hundreds of coding transcripts having important cellular functions. We thus propose nucleolin, a component of the endogenous spliceosome, through its direct binding to initiator-tRNA and its effect on latent splicing, as the first protein of a nuclear quality control mechanism regulating splice site selection to protect cells from latent splicing that can generate defective mRNAs.
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Affiliation(s)
- Kinneret Shefer
- Department of Genetics, The Hebrew University of Jerusalem, JerusalemIsrael
| | - Ayub Boulos
- Department of Genetics, The Hebrew University of Jerusalem, JerusalemIsrael
| | - Valer Gotea
- Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MDUSA
| | - Maram Arafat
- Department of Genetics, The Hebrew University of Jerusalem, JerusalemIsrael
| | - Yair Ben Chaim
- Department of Natural Sciences, The Open University, RaananaIsrael
| | - Aya Muharram
- Department of Genetics, The Hebrew University of Jerusalem, JerusalemIsrael
| | - Sara Isaac
- Department of Cell and Developmental Biology, The Hebrew University of Jerusalem, JerusalemIsrael
| | - Amir Eden
- Department of Cell and Developmental Biology, The Hebrew University of Jerusalem, JerusalemIsrael
| | - Joseph Sperling
- Department of Organic Chemistry, The Weizmann Institute of Science, RehovotIsrael
| | - Laura Elnitski
- Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MDUSA
| | - Ruth Sperling
- Department of Genetics, The Hebrew University of Jerusalem, JerusalemIsrael
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31
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Baralle M, Baralle FE. Alternative splicing and liver disease. Ann Hepatol 2021; 26:100534. [PMID: 34547477 DOI: 10.1016/j.aohep.2021.100534] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/27/2021] [Accepted: 07/30/2021] [Indexed: 02/04/2023]
Abstract
Alternative splicing produces complex and dynamic changes in the protein isoforms that are necessary for the proper biological functioning of the metabolic pathways involved in liver development and hepatocyte homeostasis. Changes in the physiological state of alternatively spliced forms are increasingly linked to liver pathologies. This may occur when the expression or function of the set of proteins controlling the alternative splicing processes are altered by external effectors such as oxidative stress and other environmental variations. Studies addressing these modifications reveal a complex interplay between the expression levels of different proteins that regulate the alternative splicing process as well as the changes in alternative splicing. This interplay results in a cascade of different protein isoforms that correlate with the progression of non-alcoholic fatty liver disease, hepatocellular carcinoma, and alcoholic liver disease. However, research on the detailed molecular mechanism underlying the production of these isoforms is needed. It is imperative to identify the physiological processes affected by the differentially spliced isoforms and confirm their role on the onset and maintenance of the pathology. This is required to design potential therapeutic approaches targeting the key splicing changes to revert the pathological condition as well as identify prognostic markers. In this review, we describe the complexity of the splicing process through an example to encourage researchers to go down this path. Subsequently, rather than a catalog of splicing events we have hand-picked and discuss a few selected studies of specific liver pathologies and suggested ways to focus research on these areas.
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Affiliation(s)
- Marco Baralle
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, Italy
| | - Francisco E Baralle
- Fondazione Italiana Fegato-Onlus, Bldg. Q, AREA Science Park, ss14, Km 163.5, Basovizza, 34149 Trieste, Italy.
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32
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Petersen USS, Doktor TK, Andresen BS. Pseudoexon activation in disease by non-splice site deep intronic sequence variation - wild type pseudoexons constitute high-risk sites in the human genome. Hum Mutat 2021; 43:103-127. [PMID: 34837434 DOI: 10.1002/humu.24306] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 11/02/2021] [Accepted: 11/06/2021] [Indexed: 12/27/2022]
Abstract
Accuracy of pre-messenger RNA (pre-mRNA) splicing is crucial for normal gene expression. Complex regulation supports the spliceosomal distinction between authentic exons and the many seemingly functional splice sites delimiting pseudoexons. Pseudoexons are nonfunctional intronic sequences that can be activated for aberrant inclusion in mRNA, which may cause disease. Pseudoexon activation is very challenging to predict, in particular when activation occurs by sequence variants that alter the splicing regulatory environment without directly affecting splice sites. As pseudoexon inclusion often evades detection due to activation of nonsense-mediated mRNA decay, and because conventional diagnostic procedures miss deep intronic sequence variation, pseudoexon activation is a heavily underreported disease mechanism. Pseudoexon characteristics have mainly been studied based on in silico predicted sequences. Moreover, because recognition of sequence variants that create or strengthen splice sites is possible by comparison with well-established consensus sequences, this type of pseudoexon activation is by far the most frequently reported. Here we review all known human disease-associated pseudoexons that carry functional splice sites and are activated by deep intronic sequence variants located outside splice site sequences. We delineate common characteristics that make this type of wild type pseudoexons distinct high-risk sites in the human genome.
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Affiliation(s)
- Ulrika S S Petersen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Thomas K Doktor
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
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33
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Scalzitti N, Kress A, Orhand R, Weber T, Moulinier L, Jeannin-Girardon A, Collet P, Poch O, Thompson JD. Spliceator: multi-species splice site prediction using convolutional neural networks. BMC Bioinformatics 2021; 22:561. [PMID: 34814826 PMCID: PMC8609763 DOI: 10.1186/s12859-021-04471-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 11/09/2021] [Indexed: 12/14/2022] Open
Abstract
Background Ab initio prediction of splice sites is an essential step in eukaryotic genome annotation. Recent predictors have exploited Deep Learning algorithms and reliable gene structures from model organisms. However, Deep Learning methods for non-model organisms are lacking. Results We developed Spliceator to predict splice sites in a wide range of species, including model and non-model organisms. Spliceator uses a convolutional neural network and is trained on carefully validated data from over 100 organisms. We show that Spliceator achieves consistently high accuracy (89–92%) compared to existing methods on independent benchmarks from human, fish, fly, worm, plant and protist organisms. Conclusions Spliceator is a new Deep Learning method trained on high-quality data, which can be used to predict splice sites in diverse organisms, ranging from human to protists, with consistently high accuracy. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04471-3.
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Affiliation(s)
- Nicolas Scalzitti
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France
| | - Arnaud Kress
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France.,BiGEst-ICube Platform, ICube Laboratory, UMR7357, 1 rue Eugène Boeckel, 67000, Strasbourg, France
| | - Romain Orhand
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France
| | - Thomas Weber
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France
| | - Luc Moulinier
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France.,BiGEst-ICube Platform, ICube Laboratory, UMR7357, 1 rue Eugène Boeckel, 67000, Strasbourg, France
| | - Anne Jeannin-Girardon
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France
| | - Pierre Collet
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France
| | - Olivier Poch
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France
| | - Julie D Thompson
- Complex Systems and Translational Bioinformatics (CSTB), ICube Laboratory, UMR7357, University of Strasbourg, 1 rue Eugène Boeckel, 67000, Strasbourg, France.
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34
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Ramírez-Moya J, Miliotis C, Baker AR, Gregory RI, Slack FJ, Santisteban P. An ADAR1-dependent RNA editing event in the cyclin-dependent kinase CDK13 promotes thyroid cancer hallmarks. Mol Cancer 2021; 20:115. [PMID: 34496885 PMCID: PMC8424981 DOI: 10.1186/s12943-021-01401-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 08/03/2021] [Indexed: 11/10/2022] Open
Abstract
Background Adenosine deaminases acting on RNA (ADARs) modify many cellular RNAs by catalyzing the conversion of adenosine to inosine (A-to-I), and their deregulation is associated with several cancers. We recently showed that A-to-I editing is elevated in thyroid tumors and that ADAR1 is functionally important for thyroid cancer cell progression. The downstream effectors regulated or edited by ADAR1 and the significance of ADAR1 deregulation in thyroid cancer remain, however, poorly defined. Methods We performed whole transcriptome sequencing to determine the consequences of ADAR1 deregulation for global gene expression, RNA splicing and editing. The effects of gene silencing or RNA editing were investigated by analyzing cell viability, proliferation, invasion and subnuclear localization, and by protein and gene expression analysis. Results We report an oncogenic function for CDK13 in thyroid cancer and identify a new ADAR1-dependent RNA editing event that occurs in the coding region of its transcript. CDK13 was significantly over-edited (c.308A > G) in tumor samples and functional analysis revealed that this editing event promoted cancer cell hallmarks. Finally, we show that CDK13 editing increases the nucleolar abundance of the protein, and that this event might explain, at least partly, the global change in splicing produced by ADAR1 deregulation. Conclusions Overall, our data support A-to-I editing as an important pathway in cancer progression and highlight novel mechanisms that might be used therapeutically in thyroid and other cancers. Supplementary Information The online version contains supplementary material available at 10.1186/s12943-021-01401-y.
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Affiliation(s)
- Julia Ramírez-Moya
- Instituto, de Investigaciones Biomédicas "Alberto Sols"; Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain.,Department of Pathology, Harvard Medical School Initiative for RNA Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Departments of Biological Chemistry and Molecular Pharmacology, and Pediatrics, Harvard Medical School, Harvard Medical School Initiative for RNA Medicine, Boston, MA, USA.,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC) Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Christos Miliotis
- Department of Pathology, Harvard Medical School Initiative for RNA Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Allison R Baker
- Department of Pathology, Harvard Medical School Initiative for RNA Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Richard I Gregory
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Departments of Biological Chemistry and Molecular Pharmacology, and Pediatrics, Harvard Medical School, Harvard Medical School Initiative for RNA Medicine, Boston, MA, USA
| | - Frank J Slack
- Department of Pathology, Harvard Medical School Initiative for RNA Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Pilar Santisteban
- Instituto, de Investigaciones Biomédicas "Alberto Sols"; Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain. .,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC) Instituto de Salud Carlos III (ISCIII), Madrid, Spain.
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35
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Lin JH, Wu H, Zou WB, Masson E, Fichou Y, Le Gac G, Cooper DN, Férec C, Liao Z, Chen JM. Splicing Outcomes of 5' Splice Site GT>GC Variants That Generate Wild-Type Transcripts Differ Significantly Between Full-Length and Minigene Splicing Assays. Front Genet 2021; 12:701652. [PMID: 34422003 PMCID: PMC8375439 DOI: 10.3389/fgene.2021.701652] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 07/13/2021] [Indexed: 12/18/2022] Open
Abstract
Combining data derived from a meta-analysis of human disease-associated 5' splice site GT>GC (i.e., +2T>C) variants and a cell culture-based full-length gene splicing assay (FLGSA) of forward engineered +2T>C substitutions, we recently estimated that ∼15-18% of +2T>C variants can generate up to 84% wild-type transcripts relative to their wild-type counterparts. Herein, we analyzed the splicing outcomes of 20 +2T>C variants that generate some wild-type transcripts in two minigene assays. We found a high discordance rate in terms of the generation of wild-type transcripts, not only between FLGSA and the minigene assays but also between the different minigene assays. In the pET01 context, all 20 wild-type minigene constructs generated the expected wild-type transcripts; of the 20 corresponding variant minigene constructs, 14 (70%) generated wild-type transcripts. In the pSPL3 context, only 18 of the 20 wild-type minigene constructs generated the expected wild-type transcripts whereas 8 of the 18 (44%) corresponding variant minigene constructs generated wild-type transcripts. Thus, in the context of a particular type of variant, we raise awareness of the limitations of minigene splicing assays and emphasize the importance of sequence context in regulating splicing. Whether or not our findings apply to other types of splice-altering variant remains to be investigated.
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Affiliation(s)
- Jin-Huan Lin
- Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China.,Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Hao Wu
- Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China.,Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Wen-Bin Zou
- Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China.,Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Emmanuelle Masson
- Univ Brest, Inserm, EFS, UMR 1078, GGB, Brest, France.,Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, Brest, France
| | - Yann Fichou
- Univ Brest, Inserm, EFS, UMR 1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Gerald Le Gac
- Univ Brest, Inserm, EFS, UMR 1078, GGB, Brest, France.,Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR 1078, GGB, Brest, France.,Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, Brest, France
| | - Zhuan Liao
- Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China.,Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR 1078, GGB, Brest, France
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36
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de Wolf B, Oghabian A, Akinyi MV, Hanks S, Tromer EC, van Hooff JJE, van Voorthuijsen L, van Rooijen LE, Verbeeren J, Uijttewaal ECH, Baltissen MPA, Yost S, Piloquet P, Vermeulen M, Snel B, Isidor B, Rahman N, Frilander MJ, Kops GJPL. Chromosomal instability by mutations in the novel minor spliceosome component CENATAC. EMBO J 2021; 40:e106536. [PMID: 34009673 PMCID: PMC8280824 DOI: 10.15252/embj.2020106536] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/22/2022] Open
Abstract
Aneuploidy is the leading cause of miscarriage and congenital birth defects, and a hallmark of cancer. Despite this strong association with human disease, the genetic causes of aneuploidy remain largely unknown. Through exome sequencing of patients with constitutional mosaic aneuploidy, we identified biallelic truncating mutations in CENATAC (CCDC84). We show that CENATAC is a novel component of the minor (U12-dependent) spliceosome that promotes splicing of a specific, rare minor intron subtype. This subtype is characterized by AT-AN splice sites and relatively high basal levels of intron retention. CENATAC depletion or expression of disease mutants resulted in excessive retention of AT-AN minor introns in ˜ 100 genes enriched for nucleocytoplasmic transport and cell cycle regulators, and caused chromosome segregation errors. Our findings reveal selectivity in minor intron splicing and suggest a link between minor spliceosome defects and constitutional aneuploidy in humans.
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Affiliation(s)
- Bas de Wolf
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
| | - Ali Oghabian
- Institute of BiotechnologyHelsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
- Present address:
Faculty of MedicineResearch Programs UnitUniversity of HelsinkiHelsinkiFinland
| | - Maureen V Akinyi
- Institute of BiotechnologyHelsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Sandra Hanks
- Division of Genetics and EpidemiologyInstitute of Cancer ResearchLondonUK
| | - Eelco C Tromer
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
- Theoretical Biology and Bioinformatics, BiologyScience FacultyUtrecht UniversityUtrechtThe Netherlands
- Present address:
Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Jolien J E van Hooff
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
- Theoretical Biology and Bioinformatics, BiologyScience FacultyUtrecht UniversityUtrechtThe Netherlands
- Present address:
Unité d'EcologieSystématique et EvolutionCNRSUniversité Paris‐SudUniversité Paris‐SaclayAgroParisTechOrsayFrance
| | - Lisa van Voorthuijsen
- Oncode InstituteDepartment of Molecular BiologyFaculty of ScienceRadboud Institute for Molecular Life ScienceRadboud University NijmegenNijmegenThe Netherlands
| | - Laura E van Rooijen
- Theoretical Biology and Bioinformatics, BiologyScience FacultyUtrecht UniversityUtrechtThe Netherlands
| | - Jens Verbeeren
- Institute of BiotechnologyHelsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Esther C H Uijttewaal
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
| | - Marijke P A Baltissen
- Oncode InstituteDepartment of Molecular BiologyFaculty of ScienceRadboud Institute for Molecular Life ScienceRadboud University NijmegenNijmegenThe Netherlands
| | - Shawn Yost
- Division of Genetics and EpidemiologyInstitute of Cancer ResearchLondonUK
| | - Philippe Piloquet
- Service de Génétique MédicaleUnité de génétique CliniqueCHU Hotel DieuNantes CedexFrance
| | - Michiel Vermeulen
- Oncode InstituteDepartment of Molecular BiologyFaculty of ScienceRadboud Institute for Molecular Life ScienceRadboud University NijmegenNijmegenThe Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, BiologyScience FacultyUtrecht UniversityUtrechtThe Netherlands
| | - Bertrand Isidor
- Service de Génétique MédicaleUnité de génétique CliniqueCHU Hotel DieuNantes CedexFrance
| | - Nazneen Rahman
- Division of Genetics and EpidemiologyInstitute of Cancer ResearchLondonUK
| | - Mikko J Frilander
- Institute of BiotechnologyHelsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Geert J P L Kops
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
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37
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Artemyeva-Isman OV, Porter ACG. U5 snRNA Interactions With Exons Ensure Splicing Precision. Front Genet 2021; 12:676971. [PMID: 34276781 PMCID: PMC8283771 DOI: 10.3389/fgene.2021.676971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/12/2021] [Indexed: 11/13/2022] Open
Abstract
Imperfect conservation of human pre-mRNA splice sites is necessary to produce alternative isoforms. This flexibility is combined with the precision of the message reading frame. Apart from intron-termini GU_AG and the branchpoint A, the most conserved are the exon-end guanine and +5G of the intron start. Association between these guanines cannot be explained solely by base-pairing with U1 snRNA in the early spliceosome complex. U6 succeeds U1 and pairs +5G in the pre-catalytic spliceosome, while U5 binds the exon end. Current U5 snRNA reconstructions by CryoEM cannot explain the conservation of the exon-end G. Conversely, human mutation analyses show that guanines of both exon termini can suppress splicing mutations. Our U5 hypothesis explains the mechanism of splicing precision and the role of these conserved guanines in the pre-catalytic spliceosome. We propose: (1) optimal binding register for human exons and U5-the exon junction positioned at U5Loop1 C39|C38; (2) common mechanism for base-pairing of human U5 snRNA with diverse exons and bacterial Ll.LtrB intron with new loci in retrotransposition-guided by base pair geometry; and (3) U5 plays a significant role in specific exon recognition in the pre-catalytic spliceosome. Statistical analyses showed increased U5 Watson-Crick pairs with the 5'exon in the absence of +5G at the intron start. In 5'exon positions -3 and -5, this effect is specific to U5 snRNA rather than U1 snRNA of the early spliceosome. Increased U5 Watson-Crick pairs with 3'exon position +1 coincide with substitutions of the conserved -3C at the intron 3'end. Based on mutation and X-ray evidence, we propose that -3C pairs with U2 G31 juxtaposing the branchpoint and the 3'intron end. The intron-termini pair, formed in the pre-catalytic spliceosome to be ready for transition after branching, and the early involvement of the 3'intron end ensure that the 3'exon contacts U5 in the pre-catalytic complex. We suggest that splicing precision is safeguarded cooperatively by U5, U6, and U2 snRNAs that stabilize the pre-catalytic complex by Watson-Crick base pairing. In addition, our new U5 model explains the splicing effect of exon-start +1G mutations: U5 Watson-Crick pairs with exon +2C/+3G strongly promote exon inclusion. We discuss potential applications for snRNA therapeutics and gene repair by reverse splicing.
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Affiliation(s)
- Olga V Artemyeva-Isman
- Gene Targeting Group, Centre for Haematology, Department of Immunology and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Andrew C G Porter
- Gene Targeting Group, Centre for Haematology, Department of Immunology and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
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38
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Riepe TV, Khan M, Roosing S, Cremers FPM, 't Hoen PAC. Benchmarking deep learning splice prediction tools using functional splice assays. Hum Mutat 2021; 42:799-810. [PMID: 33942434 PMCID: PMC8360004 DOI: 10.1002/humu.24212] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 03/16/2021] [Accepted: 04/17/2021] [Indexed: 12/21/2022]
Abstract
Hereditary disorders are frequently caused by genetic variants that affect pre-messenger RNA splicing. Though genetic variants in the canonical splice motifs are almost always disrupting splicing, the pathogenicity of variants in the noncanonical splice sites (NCSS) and deep intronic (DI) regions are difficult to predict. Multiple splice prediction tools have been developed for this purpose, with the latest tools employing deep learning algorithms. We benchmarked established and deep learning splice prediction tools on published gold standard sets of 71 NCSS and 81 DI variants in the ABCA4 gene and 61 NCSS variants in the MYBPC3 gene with functional assessment in midigene and minigene splice assays. The selection of splice prediction tools included CADD, DSSP, GeneSplicer, MaxEntScan, MMSplice, NNSPLICE, SPIDEX, SpliceAI, SpliceRover, and SpliceSiteFinder-like. The best-performing splice prediction tool for the different variants was SpliceRover for ABCA4 NCSS variants, SpliceAI for ABCA4 DI variants, and the Alamut 3/4 consensus approach (GeneSplicer, MaxEntScacn, NNSPLICE and SpliceSiteFinder-like) for NCSS variants in MYBPC3 based on the area under the receiver operator curve. Overall, the performance in a real-time clinical setting is much more modest than reported by the developers of the tools.
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Affiliation(s)
- Tabea V. Riepe
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Department of Human Genetics and Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Mubeen Khan
- Department of Human Genetics and Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Susanne Roosing
- Department of Human Genetics and Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Frans P. M. Cremers
- Department of Human Genetics and Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Peter A. C. 't Hoen
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
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39
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Abstract
PURPOSE OF REVIEW Splicing mutations are among the most recurrent genetic perturbations in hematological malignancies, highlighting an important impact of splicing regulation in hematopoietic development. However, compared to our understanding of splicing factor mutations in hematological malignancies, studies of splicing components and alternative splicing in normal hematopoiesis have been less well investigated. Here, we outline the most recent findings on splicing regulation in normal hematopoiesis and discuss the important questions in the field. RECENT FINDINGS Recent studies have highlighted the critical role of splicing regulation in hematopoiesis, including characterization of splicing components in normal hematopoiesis, investigation of transcriptional alterations on splicing, and identification of stage-specific alternative splicing events during hematopoietic development. SUMMARY These interesting findings provide insights on hematopoietic regulation at a co-transcriptional level. More high-throughput RNA ribonucleic acid (RNA) sequencing and functional genomic screens are needed to advance our knowledge of critical alternative splicing patterns in shaping hematopoiesis.
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Affiliation(s)
- Sisi Chen
- Human Oncology and Pathogenesis Program, Dept. of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Dept. of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065
- Leukemia Service, Dept. of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065
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40
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Larue GE, Eliáš M, Roy SW. Expansion and transformation of the minor spliceosomal system in the slime mold Physarum polycephalum. Curr Biol 2021; 31:3125-3131.e4. [PMID: 34015249 DOI: 10.1016/j.cub.2021.04.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/14/2021] [Accepted: 04/20/2021] [Indexed: 12/25/2022]
Abstract
Spliceosomal introns interrupt nuclear genes and are removed from RNA transcripts ("spliced") by machinery called spliceosomes. Although the vast majority of spliceosomal introns are removed by the so-called major (or "U2") spliceosome, diverse eukaryotes also contain a rare second form, the minor ("U12") spliceosome, and associated ("U12-type") introns.1-3 In all characterized species, U12-type introns are distinguished by several features, including being rare in the genome (∼0.5% of all introns),4-6 containing extended evolutionarily conserved splicing motifs,4,5,7,8 being generally ancient,9,10 and being inefficiently spliced.11-13 Here, we report a remarkable exception in the slime mold Physarum polycephalum. The P. polycephalum genome contains >20,000 U12-type introns-25 times more than any other species-enriched in a diversity of non-canonical splice boundaries as well as transformed splicing signals that appear to have co-evolved with the spliceosome due to massive gain of efficiently spliced U12-type introns. These results reveal an unappreciated dynamism of minor spliceosomal introns and spliceosomal introns in general.
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Affiliation(s)
- Graham E Larue
- Department of Molecular and Cell Biology, University of California, Merced, Merced, CA 95343, USA.
| | - Marek Eliáš
- Department of Biology and Ecology Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Scott W Roy
- Department of Molecular and Cell Biology, University of California, Merced, Merced, CA 95343, USA; Department of Biology, San Francisco State University, San Francisco, CA 94132, USA.
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Bedi K, Magnuson BR, Narayanan I, Paulsen M, Wilson TE, Ljungman M. Co-transcriptional splicing efficiencies differ within genes and between cell types. RNA (NEW YORK, N.Y.) 2021; 27:rna.078662.120. [PMID: 33975916 PMCID: PMC8208053 DOI: 10.1261/rna.078662.120] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/05/2021] [Indexed: 06/01/2023]
Abstract
Pre-mRNA splicing is carried out by the spliceosome and involves splice site recognition, removal of introns, and ligation of exons. Components of the spliceosome have been shown to interact with the elongating RNA polymerase II (RNAPII) which is thought to allow splicing to occur concurrently with transcription. However, little is known about the regulation and efficiency of co-transcriptional splicing in human cells. In this study, we used Bru-seq and BruChase-seq to determine the co-transcriptional splicing efficiencies of 17,000 introns expressed across 6 human cell lines. We found that less than half of all introns across these 6 cell lines were co-transcriptionally spliced. Splicing efficiencies for individual introns showed variations across cell lines, suggesting that splicing may be regulated in a cell-type specific manner. Moreover, the splicing efficiency of introns varied within genes. The efficiency of co-transcriptional splicing did not correlate with gene length, intron position, splice site strengths, or the intron/neighboring exons GC content. However, we identified binding signals from multiple RNA binding proteins (RBPs) that correlated with splicing efficiency, including core spliceosomal machinery components-such as SF3B4, U2AF1 and U2AF2 showing higher binding signals in poorly spliced introns. In addition, multiple RBPs, such as BUD13, PUM1 and SND1, showed preferential binding in exons that flank introns with high splicing efficiencies. The nascent RNA splicing patterns presented here across multiple cell types add to our understanding of the complexity in RNA splicing, wherein RNA-binding proteins may play important roles in determining splicing outcomes in a cell type- and intron-specific manner.
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Inoue D, Polaski JT, Taylor J, Castel P, Chen S, Kobayashi S, Hogg SJ, Hayashi Y, Pineda JMB, El Marabti E, Erickson C, Knorr K, Fukumoto M, Yamazaki H, Tanaka A, Fukui C, Lu SX, Durham BH, Liu B, Wang E, Mehta S, Zakheim D, Garippa R, Penson A, Chew GL, McCormick F, Bradley RK, Abdel-Wahab O. Minor intron retention drives clonal hematopoietic disorders and diverse cancer predisposition. Nat Genet 2021; 53:707-718. [PMID: 33846634 PMCID: PMC8177065 DOI: 10.1038/s41588-021-00828-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 02/24/2021] [Indexed: 12/13/2022]
Abstract
Most eukaryotes harbor two distinct pre-mRNA splicing machineries: the major spliceosome, which removes >99% of introns, and the minor spliceosome, which removes rare, evolutionarily conserved introns. Although hypothesized to serve important regulatory functions, physiologic roles of the minor spliceosome are not well understood. For example, the minor spliceosome component ZRSR2 is subject to recurrent, leukemia-associated mutations, yet functional connections among minor introns, hematopoiesis and cancers are unclear. Here, we identify that impaired minor intron excision via ZRSR2 loss enhances hematopoietic stem cell self-renewal. CRISPR screens mimicking nonsense-mediated decay of minor intron-containing mRNA species converged on LZTR1, a regulator of RAS-related GTPases. LZTR1 minor intron retention was also discovered in the RASopathy Noonan syndrome, due to intronic mutations disrupting splicing and diverse solid tumors. These data uncover minor intron recognition as a regulator of hematopoiesis, noncoding mutations within minor introns as potential cancer drivers and links among ZRSR2 mutations, LZTR1 regulation and leukemias.
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Affiliation(s)
- Daichi Inoue
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Japan
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Jacob T Polaski
- Public Health Sciences and Basic Sciences Divisions, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Justin Taylor
- Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, Miami, FL, USA
| | - Pau Castel
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, USA
| | - Sisi Chen
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Susumu Kobayashi
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Japan
- Division of Cellular Therapy, The Institute of Medical Science, the University of Tokyo, Tokyo, Japan
| | - Simon J Hogg
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Yasutaka Hayashi
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Japan
| | - Jose Mario Bello Pineda
- Public Health Sciences and Basic Sciences Divisions, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Ettaib El Marabti
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Caroline Erickson
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Katherine Knorr
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Miki Fukumoto
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Japan
| | - Hiromi Yamazaki
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Japan
| | - Atsushi Tanaka
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Japan
- Department of Immunology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Chie Fukui
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Japan
| | - Sydney X Lu
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Benjamin H Durham
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Bo Liu
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Eric Wang
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Sanjoy Mehta
- Gene Editing & Screening Facility, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Daniel Zakheim
- Gene Editing & Screening Facility, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ralph Garippa
- Gene Editing & Screening Facility, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Alex Penson
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA
| | - Guo-Liang Chew
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Frank McCormick
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, USA
| | - Robert K Bradley
- Public Health Sciences and Basic Sciences Divisions, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan KetterAbsolute numbers of live mature hematopoietic cellsing Cancer Center, New York, NY, USA.
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43
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Fadaie Z, Whelan L, Dockery A, Li CHZ, van den Born LI, Hoyng CB, Gilissen C, Corominas J, Rowlands C, Megaw R, Lampe AK, Cremers FPM, Farrar GJ, Ellingford JM, Kenna PF, Roosing S. BBS1 branchpoint variant is associated with non-syndromic retinitis pigmentosa. J Med Genet 2021; 59:438-444. [PMID: 33910932 DOI: 10.1136/jmedgenet-2020-107626] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/11/2021] [Accepted: 02/26/2021] [Indexed: 11/03/2022]
Abstract
BACKGROUND Inherited retinal diseases (IRDs) can be caused by variants in >270 genes. The Bardet-Biedl syndrome 1 (BBS1) gene is one of these genes and may be associated with syndromic and non-syndromic autosomal recessive retinitis pigmentosa (RP). Here, we identified a branchpoint variant in BBS1 and assessed its pathogenicity by in vitro functional analysis. METHODS Whole genome sequencing was performed for three unrelated monoallelic BBS1 cases with non-syndromic RP. A fourth case received MGCM 105 gene panel analysis. Functional analysis using a midigene splice assay was performed for the putative pathogenic branchpoint variant in BBS1. After confirmation of its pathogenicity, patients were clinically re-evaluated, including assessment of non-ocular features of Bardet-Biedl syndrome. RESULTS Clinical assessments of probands showed that all individuals displayed non-syndromic RP with macular involvement. Through detailed variant analysis and prioritisation, two pathogenic variants in BBS1, the most common missense variant, c.1169T>G (p.(Met390Arg)), and a branchpoint variant, c.592-21A>T, were identified. Segregation analysis confirmed that in all families, probands were compound heterozygous for c.1169T>G and c.592-21A>T. Functional analysis of the branchpoint variant revealed a complex splicing defect including exon 8 and exon 7/8 skipping, and partial in-frame deletion of exon 8. CONCLUSION A putative severe branchpoint variant in BBS1, together with a mild missense variant, underlies non-syndromic RP in four unrelated individuals. To our knowledge, this is the first report of a pathogenic branchpoint variant in IRDs that results in a complex splice defect. In addition, this research highlights the importance of the analysis of non-coding regions in order to provide a conclusive molecular diagnosis.
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Affiliation(s)
- Zeinab Fadaie
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
| | - Laura Whelan
- School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Adrian Dockery
- School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Catherina H Z Li
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
- Department of Ophthalmology, Radboudumc, Nijmegen, The Netherlands
| | | | - Carel B Hoyng
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
- Department of Ophthalmology, Radboudumc, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Radboud Institute of Molecular Life Sciences, RadboudUMC, Nijmegen, The Netherlands
| | - Jordi Corominas
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Radboud Institute of Molecular Life Sciences, RadboudUMC, Nijmegen, The Netherlands
| | - Charlie Rowlands
- North West Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, St Mary's Hospital, Manchester, UK
- Division of Evolution and Genomic Sciences, Neuroscience and Mental Health Domain, The University of Manchester Faculty of Biology Medicine and Health, Manchester, UK
| | - Roly Megaw
- MRC Human Genetics Unit, University of Edinburgh Western General Hospital, Edinburgh, UK
- Princess Alexandra Eye Pavilion, Department of Ophthalmology, University of Edinburgh Western General Hospital, Edinburgh, UK
| | - Anne K Lampe
- South East of Scotland Clinical Genetics Service, Western General Hospital, Edinburgh, UK
| | - Frans P M Cremers
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
| | - Gwyneth Jane Farrar
- School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Jamie M Ellingford
- North West Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, St Mary's Hospital, Manchester, UK
- Division of Evolution and Genomic Sciences, Neuroscience and Mental Health Domain, The University of Manchester Faculty of Biology Medicine and Health, Manchester, UK
| | - Paul F Kenna
- School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
- Research Foundation, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Susanne Roosing
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
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44
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Madan V, Cao Z, Teoh WW, Dakle P, Han L, Shyamsunder P, Jeitany M, Zhou S, Li J, Nordin HBM, Shi J, Yu S, Yang H, Hossain MZ, Chng WJ, Koeffler HP. ZRSR1 cooperates with ZRSR2 in regulating splicing of U12-type introns in murine hematopoietic cells. Haematologica 2021; 107:680-689. [PMID: 33691379 PMCID: PMC8883539 DOI: 10.3324/haematol.2020.260562] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Indexed: 12/03/2022] Open
Abstract
Recurrent loss-of-function mutations of spliceosome gene, ZRSR2, occur in myelodysplastic syndromes (MDS). Mutation/loss of ZRSR2 in human myeloid cells primarily causes impaired splicing of the U12-type introns. In order to further investigate the role of this splice factor in RNA splicing and hematopoietic development, we generated mice lacking ZRSR2. Unexpectedly, Zrsr2-deficient mice developed normal hematopoiesis with no abnormalities in myeloid differentiation evident in either young or ≥1-year old knockout mice. Repopulation ability of Zrsr2-deficient hematopoietic stem cells was also unaffected in both competitive and non-competitive reconstitution assays. Myeloid progenitors lacking ZRSR2 exhibited mis-splicing of U12-type introns, however, this phenotype was moderate compared to the ZRSR2-deficient human cells. Our investigations revealed that a closely related homolog, Zrsr1, expressed in the murine hematopoietic cells, but not in human cells contributes to splicing of U12-type introns. Depletion of Zrsr1 in Zrsr2 KO myeloid cells exacerbated retention of the U12-type introns, thus highlighting a collective role of ZRSR1 and ZRSR2 in murine U12-spliceosome. We also demonstrate that aberrant retention of U12-type introns of MAPK9 and MAPK14 leads to their reduced protein expression. Overall, our findings highlight that both ZRSR1 and ZRSR2 are functional components of the murine U12-spliceosome, and depletion of both proteins is required to accurately model ZRSR2-mutant MDS in mice.
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Affiliation(s)
- Vikas Madan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.
| | - Zeya Cao
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Weoi Woon Teoh
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Pushkar Dakle
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Lin Han
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Pavithra Shyamsunder
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Programme in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore
| | - Maya Jeitany
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore
| | - Siqin Zhou
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Jia Li
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | | | - JiZhong Shi
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Shuizhou Yu
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Md Zakir Hossain
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Wee Joo Chng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Hematology-Oncology, National University Cancer Institute, NUHS, Singapore
| | - H Phillip Koeffler
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Cedars-Sinai Medical Center, Division of Hematology/Oncology, UCLA School of Medicine, Los Angeles, USA; National University Cancer Institute, National University Hospital Singapore, Singapore
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45
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Parker MT, Knop K, Barton GJ, Simpson GG. 2passtools: two-pass alignment using machine-learning-filtered splice junctions increases the accuracy of intron detection in long-read RNA sequencing. Genome Biol 2021; 22:72. [PMID: 33648554 PMCID: PMC7919322 DOI: 10.1186/s13059-021-02296-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 02/10/2021] [Indexed: 01/04/2023] Open
Abstract
Transcription of eukaryotic genomes involves complex alternative processing of RNAs. Sequencing of full-length RNAs using long reads reveals the true complexity of processing. However, the relatively high error rates of long-read sequencing technologies can reduce the accuracy of intron identification. Here we apply alignment metrics and machine-learning-derived sequence information to filter spurious splice junctions from long-read alignments and use the remaining junctions to guide realignment in a two-pass approach. This method, available in the software package 2passtools (https://github.com/bartongroup/2passtools), improves the accuracy of spliced alignment and transcriptome assembly for species both with and without existing high-quality annotations.
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Affiliation(s)
- Matthew T Parker
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK.
| | - Katarzyna Knop
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Geoffrey J Barton
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Gordon G Simpson
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK. .,James Hutton Institute, Invergowrie, DD2 5DA, UK.
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46
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Moya-Mendez ME, Mueller DM, Pratt M, Bonner M, Elliott C, Hunanyan A, Kucera G, Bock C, Prange L, Jasien J, Keough K, Shashi V, McDonald M, Mikati MA. Early onset severe ATP1A2 epileptic encephalopathy: Clinical characteristics and underlying mutations. Epilepsy Behav 2021; 116:107732. [PMID: 33493807 PMCID: PMC7940561 DOI: 10.1016/j.yebeh.2020.107732] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/09/2020] [Accepted: 12/20/2020] [Indexed: 01/26/2023]
Abstract
BACKGROUND ATP1A2 mutations cause hemiplegic migraine with or without epilepsy or acute reversible encephalopathy. Typical onset is in adulthood or older childhood without subsequent severe long-term developmental impairments. AIM We aimed to describe the manifestations of early onset severe ATP1A2-related epileptic encephalopathy and its underlying mutations in a cohort of seven patients. METHODS A retrospective chart review of a cohort of seven patients was conducted. Response to open-label memantine therapy, used off-label due to its NMDA receptor antagonist effects, was assessed by the Global Rating Scale of Change (GRSC) and Clinical Global Impression Scale of Improvement (CGI-I) methodologies. Molecular modeling was performed using PyMol program. RESULTS Patients (age 2.5-20 years) had symptom onset at an early age (6 days-1 year). Seizures were either focal or generalized. Common features were: drug resistance, recurrent status epilepticus, etc., severe developmental delay with episodes of acute severe encephalopathy often with headaches, dystonias, hemiplegias, seizures, and developmental regression. All had variants predicted to be disease causing (p.Ile293Met, p.Glu1000Lys, c.1017+5G>A, p.Leu809Arg, and 3 patients with p.Met813Lys). Modeling revealed that mutations interfered with ATP1A2 ion binding and translocation sites. Memantine, given to five, was tolerated in all (mean treatment: 2.3 years, range 6 weeks-4.8 years) with some improvements reported in all five. CONCLUSIONS Our observations describe a distinctive clinical profile of seven unrelated probands with early onset severe ATP1A2-related epileptic encephalopathy, provide insights into structure-function relationships of ATP1A2 mutations, and support further studies of NMDAR antagonist therapy in ATP1A2-encephalopathy.
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Affiliation(s)
- Mary E. Moya-Mendez
- Department of Pediatrics, Division of Pediatric Neurology and Developmental Medicine, Duke University, Durham, NC, United States
| | - David M. Mueller
- Center for Genetic Diseases, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, Chicago, IL, United States
| | - Milton Pratt
- Department of Pediatrics, Division of Pediatric Neurology and Developmental Medicine, Duke University, Durham, NC, United States
| | - Melanie Bonner
- Department of Psychiatry, Duke University, Durham, NC, United States
| | - Courtney Elliott
- Department of Pediatrics, Division of Pediatric Neurology and Developmental Medicine, Duke University, Durham, NC, United States
| | - Arsen Hunanyan
- Department of Pediatrics, Division of Pediatric Neurology and Developmental Medicine, Duke University, Durham, NC, United States
| | - Gary Kucera
- Duke Cancer Institute Rodent Cancer Models Shared Resource, Duke University Medical Center, Durham, NC, United States
| | - Cheryl Bock
- Duke Cancer Institute Rodent Cancer Models Shared Resource, Duke University Medical Center, Durham, NC, United States
| | - Lyndsey Prange
- Department of Pediatrics, Division of Pediatric Neurology and Developmental Medicine, Duke University, Durham, NC, United States
| | - Joan Jasien
- Department of Pediatrics, Division of Pediatric Neurology and Developmental Medicine, Duke University, Durham, NC, United States
| | - Karen Keough
- Dell Medical School at the University of Texas, Austin TX, United States
| | - Vandana Shashi
- Dell Medical School at the University of Texas, Austin TX, United States
| | - Marie McDonald
- Dell Medical School at the University of Texas, Austin TX, United States
| | - Mohamad A. Mikati
- Department of Pediatrics, Division of Pediatric Neurology and Developmental Medicine, Duke University, Durham, NC, United States,Department of Neurobiology, Duke University, Durham, NC, United States,Corresponding Author: Mohamad Mikati, MD, Children Health Center, T913J, Duke University Medical Center, 2301 Erwin Road, Durham, NC 27710, Phone: 919-668-4073, Fax: 919-681-8943,
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47
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Bai R, Wan R, Wang L, Xu K, Zhang Q, Lei J, Shi Y. Structure of the activated human minor spliceosome. Science 2021; 371:science.abg0879. [PMID: 33509932 DOI: 10.1126/science.abg0879] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/18/2021] [Indexed: 12/31/2022]
Abstract
The minor spliceosome mediates splicing of the rare but essential U12-type precursor messenger RNA. Here, we report the atomic features of the activated human minor spliceosome determined by cryo-electron microscopy at 2.9-angstrom resolution. The 5' splice site and branch point sequence of the U12-type intron are recognized by the U6atac and U12 small nuclear RNAs (snRNAs), respectively. Five newly identified proteins stabilize the conformation of the catalytic center: The zinc finger protein SCNM1 functionally mimics the SF3a complex of the major spliceosome, the RBM48-ARMC7 complex binds the γ-monomethyl phosphate cap at the 5' end of U6atac snRNA, the U-box protein PPIL2 coordinates loop I of U5 snRNA and stabilizes U5 small nuclear ribonucleoprotein (snRNP), and CRIPT stabilizes U12 snRNP. Our study provides a framework for the mechanistic understanding of the function of the human minor spliceosome.
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Affiliation(s)
- Rui Bai
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China
| | - Ruixue Wan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China. .,Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China
| | - Lin Wang
- Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Kui Xu
- Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiangfeng Zhang
- Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianlin Lei
- Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.,Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China. .,Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
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48
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Parada GE, Munita R, Georgakopoulos-Soares I, Fernandes HJR, Kedlian VR, Metzakopian E, Andres ME, Miska EA, Hemberg M. MicroExonator enables systematic discovery and quantification of microexons across mouse embryonic development. Genome Biol 2021; 22:43. [PMID: 33482885 PMCID: PMC7821500 DOI: 10.1186/s13059-020-02246-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Microexons, exons that are ≤ 30 nucleotides, are a highly conserved and dynamically regulated set of cassette exons. They have key roles in nervous system development and function, as evidenced by recent results demonstrating the impact of microexons on behaviour and cognition. However, microexons are often overlooked due to the difficulty of detecting them using standard RNA-seq aligners. RESULTS Here, we present MicroExonator, a novel pipeline for reproducible de novo discovery and quantification of microexons. We process 289 RNA-seq datasets from eighteen mouse tissues corresponding to nine embryonic and postnatal stages, providing the most comprehensive survey of microexons available for mice. We detect 2984 microexons, 332 of which are differentially spliced throughout mouse embryonic brain development, including 29 that are not present in mouse transcript annotation databases. Unsupervised clustering of microexons based on their inclusion patterns segregates brain tissues by developmental time, and further analysis suggests a key function for microexons in axon growth and synapse formation. Finally, we analyse single-cell RNA-seq data from the mouse visual cortex, and for the first time, we report differential inclusion between neuronal subpopulations, suggesting that some microexons could be cell type-specific. CONCLUSIONS MicroExonator facilitates the investigation of microexons in transcriptome studies, particularly when analysing large volumes of data. As a proof of principle, we use MicroExonator to analyse a large collection of both mouse bulk and single-cell RNA-seq datasets. The analyses enabled the discovery of previously uncharacterized microexons, and our study provides a comprehensive microexon inclusion catalogue during mouse development.
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Affiliation(s)
- Guillermo E Parada
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Roberto Munita
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ilias Georgakopoulos-Soares
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Hugo J R Fernandes
- UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0AH, UK
| | - Veronika R Kedlian
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Emmanouil Metzakopian
- UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0AH, UK
| | - Maria Estela Andres
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Eric A Miska
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK.
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
| | - Martin Hemberg
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK.
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
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49
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Nix P, Mundt E, Coffee B, Goossen E, Warf BM, Brown K, Bowles K, Roa B. Interpretation of BRCA2 Splicing Variants: A Case Series of Challenging Variant Interpretations and the Importance of Functional RNA Analysis. Fam Cancer 2021; 21:7-19. [PMID: 33469799 PMCID: PMC8799590 DOI: 10.1007/s10689-020-00224-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 12/15/2020] [Indexed: 11/13/2022]
Abstract
A substantial proportion of pathogenic variants associated with an increased risk of hereditary cancer are sequence variants affecting RNA splicing. The classification of these variants can be complex when both non-functional and functional transcripts are produced from the variant allele. We present four BRCA2 splice site variants with complex variant interpretations (BRCA2 c.68-3T>G, c.68-2A>G, c.425G>T, c.8331+2T>C). Evidence supporting a pathogenic classification is available for each variant, including in silico models, absence in population databases, and published functional data. However, comprehensive RNA analysis showed that some functional transcript may be produced by each variant. BRCA2 c.68-3T>G results in a partial splice defect. For BRCA2 c.68-2A>G and c.425G>T, aberrant splicing was shown to produce a potentially functional, in-frame transcript. BRCA2 c.8331+2T>C may utilize a functional GC donor in place of the wild-type GT donor. The severity of cancer history for carriers of these variants was also assessed using a history weighting algorithm and was not consistent with pathogenic controls (carriers of known pathogenic variants in BRCA2). Due to the conflicting evidence, our laboratory classifies these BRCA2 variants as variants of uncertain significance. This highlights the importance of evaluating new and existing evidence to ensure accurate variant classification and appropriate patient care.
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Affiliation(s)
- Paola Nix
- Myriad Genetics, Inc., 320 Wakara Way, Salt Lake City, UT, USA.
| | - Erin Mundt
- Myriad Genetics, Inc., 320 Wakara Way, Salt Lake City, UT, USA
| | - Bradford Coffee
- Myriad Genetics, Inc., 320 Wakara Way, Salt Lake City, UT, USA
| | | | - Bryan M Warf
- Myriad Genetics, Inc., 320 Wakara Way, Salt Lake City, UT, USA.,Third Wave Analytics, Inc., San Francisco, CA, USA
| | - Krystal Brown
- Myriad Genetics, Inc., 320 Wakara Way, Salt Lake City, UT, USA
| | - Karla Bowles
- Myriad Genetics, Inc., 320 Wakara Way, Salt Lake City, UT, USA
| | - Benjamin Roa
- Myriad Genetics, Inc., 320 Wakara Way, Salt Lake City, UT, USA
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50
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Aljohani MD, El Mouridi S, Priyadarshini M, Vargas-Velazquez AM, Frøkjær-Jensen C. Engineering rules that minimize germline silencing of transgenes in simple extrachromosomal arrays in C. elegans. Nat Commun 2020; 11:6300. [PMID: 33298957 PMCID: PMC7725773 DOI: 10.1038/s41467-020-19898-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/05/2020] [Indexed: 12/29/2022] Open
Abstract
Transgenes are prone to progressive silencing due to their structure, copy number, and genomic location. In C. elegans, repressive mechanisms are particularly strong in the germline with almost fully penetrant transgene silencing in simple extrachromosomal arrays and frequent silencing of single-copy transgene insertions. A class of non-coding DNA, Periodic An/Tn Clusters (PATCs) can prevent transgene-silencing in repressive chromatin or from small interfering RNAs (piRNAs). Here, we describe design rules (codon-optimization, intron and PATC inclusion, elevated temperature (25 °C), and vector backbone removal) for efficient germline expression from arrays in wildtype animals. We generate web-based tools to analyze PATCs and reagents for the convenient assembly of PATC-rich transgenes. An extensive collection of silencing resistant fluorescent proteins (e.g., gfp, mCherry, and tagBFP) can be used for dissecting germline regulatory elements and a set of enhanced enzymes (Mos1 transposase, Cas9, Cre, and Flp recombinases) enable efficient genetic engineering in C. elegans.
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Affiliation(s)
- Mohammed D Aljohani
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Sonia El Mouridi
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Monika Priyadarshini
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Amhed M Vargas-Velazquez
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Christian Frøkjær-Jensen
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia.
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